Chemical Bonding. Concepts. Introduction

Size: px
Start display at page:

Download "Chemical Bonding. Concepts. Introduction"

Transcription

1 Chemical Bonding Concepts (i) Formation of a chemical bond (iii) Lewis theory (ii) Nature of a chemical bond (iv) Types of chemical bond Introduction Though the periodic table has a place for 118 elements, there are obviously more substances in nature than 118 pure elements. This is because atoms of elements can react with one another to form new substances called compounds. When two or more elements combine, the resulting compound is unique both chemically and physically from its parent atoms. For example, sodium is a silver coloured metal that reacts so violently with water that flames are produced when sodium gets wet. The element chlorine is greenish coloured gas that is so poisonous that it was used as a weapon in world war I. When chemically bonded together, these two dangerous substances form the compound sodium chloride, a compound so safe that we eat it every day common table salt. Formation of a chemical bond Free atoms of elements are in random motion and possess some energy. Farther the atoms are, greater is their energy and lesser is the stability. Two or more atoms unite to form a molecule because in doing so, the energy of the united atoms is lowered. Thus the molecule becomes stable in comparison to separate atoms. In other words, a stable chemical union called bond between two or more atoms comes into existence only if the energy is lowered when the atoms come in close vicinity. The lower the energy of the molecule, the stronger the bond and more is the stability to the bonded atoms. Nature of chemical bond A chemical bond is an attraction between atoms. It is the attraction caused by the electromagnetic force between opposing charges either between electrons and nuclei or as the result of a dipole attraction. Since opposite charges attract via a simple electromagnetic force, the negatively charged electrons revolving round the nucleus and the positively charged protons in the nucleus attract each other. Also an electron positioned between two nuclei will be attracted to both of them. Thus, the most stable configuration of nuclei and electrons is one in which the electrons spend more time between nuclei than anywhere else in space. These electrons cause the nuclei to be attracted to each other and this attraction results in the bond. Electrons occupy large

2 volume compared to the nuclei and this volume keeps the atomic nuclei relatively far apart as compared with the size of the nuclei themselves. 2 The force of attraction which holds the two atoms together in a molecule is called a chemical bond. Lewis theory In 1916, an American chemist, Lewis proposed that chemical bonds are formed between atoms because electrons from the atoms interact with each other. Lewis had observed that many elements are most stable when they contain eight electrons in their outermost or valence shell of the atom. He suggested that atoms with fewer than eight electrons bond together to share electrons and complete their valence shell. While some of Lewis predictions have since been proven incorrect ( he suggested that electrons occupy cube shaped orbitals ), his work established the basis of what is known today about chemical bonding. Essentials of Lewis theory Between 1916 and 1919, Lewis, Kossel and Langmuir made several important proposals on bonding which lead to the development of Lewis theory of bonding. 1) Valence electrons mainly play a fundamental role in bonding. 2) Ionic bonding involves the transfer of one or more electrons from one atom to another. 3) Covalent bonding involves sharing of electrons between atoms. 4) Electrons are transferred or shared between atoms such that each atom achieves the electron configuration of a noble gas i.e. having eight electrons in the outermost shell called octet. 5) This arrangement is called octet rule. ( Exception He) 6) Exceptions to octet rule may occur. Lewis proposed symbols which represent the resulting structures that follow the octet rule. In a Lewis symbol, an element is surrounded by up to 8 dots where elemental symbol represents the nucleus and the dots represents the valence electrons. Activity 1 - Draw the Lewis dot formula for following molecules - BF 3, KCl

3 3 Types of chemical bonds Following figure shows a road map of chemical bonding i.e. which elements will form which type of bond Figure 1 Periodic table and elements forming different types of bonds.

4 4 Chemical bonds can be divided into three major types : ionic bonds which occur between a metal and a non-metal; covalent bonds which occur between two non-metals; and metallic bonds which occur within metals. Some people consider hydrogen bond as a separate type of bond. In an ionic bond, one or more electrons are transferred from metal to non-metal and the resultant ions are attracted to each other by coulombic forces. In a covalent bond, non-metals share electrons that interact with the nuclei of both atoms via coulombic forces, holding the atoms together. In a metallic bond, the atoms form a lattice in which each metal atom loses electrons to an electron sea. The attraction of the positively charged metal ions to the electron - sea holds the metal atoms together. Hydrogen bond occurs in some restricted hydrides. In addition, there are dipole dipole interactions and van der Waals forces which are small in magnitude and play a role in bonding limited substances.. Activity 2 Select one element from left hand side, one element from the right hand side and one element from the middle of the periodic table. Predict how many types of bonds each element can form with its own atoms as well as other atoms. Check your understanding (i) Why do atoms tend to combine and form a bond? (ii) When atoms come close, which forces come into existence? (iii) What is Lewis theory of bond formation? (iv) How many main types of bonds are known?

5 5 Concepts (i) Formation of ionic bond (iii) Formation of cation and anion (ii) Characteristic properties of ionic compounds (iv) Difference between atoms and ions Formation of ionic bond An ionic bond ( also called as electrovalent bond ) is a type of chemical bond that involves a metal ion and a non-metal ion ( or polyatomic ions such as ammonium ) through electrostatic attraction. In short, it is a bond formed by the attraction between two oppositely charged ions. The metal donates one or more electrons, forming a positively charged ion or cation with a stable electron configuration. These electrons then enter the non-metal, causing it to form a negatively charged ion or anion which also has a stable electron configuration. The electrostatic attraction between the oppositely charged ions causes them to come together and form a bond. For example, when sodium ( Na ) and chlorine ( Cl) are combined, the sodium atoms each lose an electron, forming a cation (Na + ) and the chlorine atoms each gain an electron to form an anion (Cl - ). These ions then are attracted to each other in 1:1 proportion to form sodium chloride NaCl. Na + Cl Na + + Cl - NaCl Figure 2 - Combination of Na and Cl to form Na + and Cl - The electrostatic force of attraction between two oppositely charged ions formed by transfer of electrons from one atom to another is called an ionic or electrovalent bond.

6 The figure given below shows the variation of potential energy as a function of distance of separation between sodium or chlorine atoms. An atom of sodium has one electron extra outside the closed shell and it takes 5.14 electron volts of energy to remove that electron (its ionization potential is 5.14 ev). 6 ( diagram is not to the scale) Figure 3 P.E. diagram for NaCl molecule The chlorine atom is short of one electron to fill a shell and it releases 3.62 electron volts when it acquires that electron ( its electron affinity is 3.62 ev). This means that it takes only 1.52 ev( ) of energy to donate one of the sodium electrons to chlorine when they are far apart. When the resultant ions are brought close together, their electric potential becomes more and more negative, reaching 1.52 ev at about 0.94 nm separation. This means that if neutral sodium and chlorine atoms found themselves closer than 0.94 nm, it would be energetically favourable to transfer electron from Na to Cl and form the ionic bond. The potential energy curve shows that there is a minimum at nm separation and then a steep rise in potential which represents a repulsive force. This repulsive force is more than just an electrostatic repulsion between the electron clouds of the two atoms. The removal of electron from the atom is endothermic and causes the ions to have a higher energy. There may also be energy changes associated with breaking of existing bonds or the addition of more than one electron to form anions. However, the attraction of the ions to each other lowers their energy.

7 The energy balance cycle for NaCl is shown below. (i) Gaseous sodium atom is formed from solid sodium metal Na (s) kj mol -1 Na(g) (ii) Sodium ion is formed from gaseous sodium atom. Na (g) kj mol -1 Na + (g) + e - (iii) Chlorine molecule dissociates into gaseous chlorine atoms. ½ Cl 2 (g) kj mol -1 Cl (g) (iv) Chloride ion is formed from gaseous chlorine atom. Cl (g) + e - Cl - (g) kj mol -1 (v) Sodium ions and chloride ions interact to form solid sodium chloride. Na + (g) + Cl - (g) Na + Cl - (s) kj mol Energy evolved = = 1136 kj Energy absorbed = = 725 kj Energy evolved = 411 kj mol -1 Ionic bonding will occur only if the overall energy change for the reaction is favourable when the bonded atoms have a lower energy than the free ones. The larger the resulting energy change, the stronger the bond. The low electronegativity of the metals and high electronegativity of non-metals means that the energy change of the reaction is most favourable when metals lose electrons and non-metals gain electrons. Notice that when sodium loses its one valence electron, it gets smaller in size, while chlorine grows larger when it gains an additional valence electron. This is typical of the relative sizes of the ions to atoms. Positive ions tend to be smaller than the parent atoms while negative ions tend to be larger than their parent. After the reaction takes place, the charged Na + and Cl - ions are held together by electrostatic forces, thus forming an ionic bond. Activity 3 - You are given following data All energy values are in kj mol -1 (i) Sublimation energy of K = 89.2 (ii) Ionisation energy of K = (iii) Dissociation energy of F 2 = (iv) Electron affinity of F = (v) Lattice energy of KF = (vi) Electronegativity of K = 0.82 ( vii) Electronegativity of F = 4 What type of bond K and F will form and energetically will KF be stable?

8 8 Activity 4 From the crystal structure of sodium chloride given in the book, find out the coordination number of Na + ion and Cl - ion and try to draw yourself the structure of NaCl. Other examples of ionic bonding As stated earlier, more the difference in electronegativity of the two atoms, more are the chances of forming ionic bonds. For example, two potassium atoms can lose one electron each to oxygen atom and potassium and oxygen may combine to form ionic bond. Similarly, rubidium and fluorine atom, magnesium and chlorine atom, calcium and oxygen atom can form ionic bond. Characteristic Properties of Ionic Compounds Ionic compounds have following characteristic properties. 1) Ionic compounds involve ionic bonds which are formed between metals and non-metals. 2) In naming simple ionic compounds, the metal is always first, the non-metal second ( e.g. sodium chloride ) 3) Ionic compounds dissolve easily in water and other polar solvents. 4) In solution and in molten state ionic compounds easily conduct electricity. 5) Ionic compounds tend to form crystalline solids with high melting temperatures. Pure ionic bonding is not known to exist. All ionic compounds have a degree of covalent bonding. The larger the difference in electronegativity between two atoms, the more ionic the bond. Formation of cation and anion (i) When an atom loses electron, it gets an overall positive charge because the number of protons now exceed the number of electrons. The positively charged ion is called a cation. The process of formation of a cation from its atom is called oxidation. (ii) When an atom gains electron, it gets an overall negative charge because the number of electrons now exceed the number of protons. The negatively charged ion is called an anion. The process of formation of an anion from its atom is called reduction.

9 9 Difference between atoms and ions Atoms Ions (i) Atoms are electrically neutral because (i) Ions are charged particles because of protons and electrons are equal in number. imbalance of protons and electrons. (ii) The outermost shell may or may not (ii) The outermost shell has a completed have a completed duplet or octet e.g duplet or octet e.g. Ne = 2,8 ( completed octet ) Cl - = 2,8 ( completed octet ) Na = 2,8,1 ( incomplete octet ) Li + = 2 ( completed duplet ) (iii) Atoms may be or may not be capable of (iii) Ions are capable of independent free existence e.g. existence in solution or gaseous state He atom exists in uncombined state e.g. NaCl Na + + Cl - ( in solution) Hydrogen ( H 2 ) exists in combined Na Na + + e - (Gaseous) state Check your understanding (i) Which elements in the periodic table tend to form ionic bond? (ii) In terms of electronegativity, what is the condition for formation of an ionic bond? (iii) What is the criterion to know whether the ionic compound will be stable or not? (iv) Which pair of elements in the periodic table will form the strongest ionic bond? (v) Why is it that the process of formation of cation is called oxidation and formation of anion is called reduction?

10 10 Concepts (i) Formation of covalent bond (iii) Polar and non-polar covalent bonds (iv) Coordinate bond (ii) Multiple bonds (v) Characteristics of covalent compounds Formation of covalent bond The second major type of chemical bond occurs when atoms share electrons. As opposed to ionic bonding in which a complete transfer of electrons occurs, covalent bonding occurs when two ( or more ) elements share electrons. Covalent bonding occurs because the atoms in the molecule have a similar tendency for electrons ( generally to gain electrons.) This most commonly occurs when two non-metals bond together. Because both of the non-metals want to gain electrons, the elements involved will share electrons in an effort to fill their valence shells. A good example of a covalent bond is that which occurs between two hydrogen atoms. Atoms of hydrogen (H) have one valence electron in their electron shell. Since the capacity of this shell is two electrons, each hydrogen atom will want to pick up a second electron. In an effort to pick up a second electron, hydrogen atoms will react with nearby hydrogen (H) atoms to form the molecule H 2. Since the hydrogen molecule is a combination of equally matched atoms, the atoms will share each other s single electron, forming one covalent bond. In this way, both atoms share the stability of a full valence shell. A chemical bond formed by sharing of electrons between atoms is called a covalent bond. As the two hydrogen atoms approach one another, in addition to nucleus electron attraction, nuclear-nuclear repulsion and electron electron repulsion also come into existence. When the two hydrogen atoms are at a distance of nm, the potential energy of the two hydrogen atoms together is at its minimum and releases 4.52 ev. At this stage, a chemical bond is formed. If the hydrogen atoms come still closer, the potential energy rises steeply making the molecule unstable. Thus, the sharing of electrons is energetically favourable to both the hydrogen atoms with the formation of stable single covalent bond. The figure given below shows the variation of potential energy as a function of distance of separation of hydrogen atoms.

11 11 ( diagram is not to the scale) Figure 4 P.E. diagram for H 2 molecule Following figure shows the formation of single covalent bond between two hydrogen atoms and two chlorine atoms. Figure 5 - Bonding in H 2 and Cl 2 molecule

12 12 Two or more atoms of different elements can also share electrons to form a single bond between them and complete the octet ( or duplet ) of each atom. For example, in methane, one carbon and four hydrogen atoms share one electron pair each to form four C - H bonds, in ammonia, one nitrogen and three hydrogen atoms share one electron pair each to form three N H bonds and in water, one oxygen and two hydrogen atoms share one electron pair each to form two O H bonds. This is shown in the following diagram. Multiple bonds Figure 6 Bonding in H 2 O, NH 3 and CH 4 molecules For every pair of electrons shared between two atoms, a single covalent bond is formed. Some atoms can share two or three pairs of electrons forming multiple bonds i. e. a double or triple bonds. For example, oxygen atom has six electrons in its outermost shell. It needs two electrons to complete its octet and attains the configuration of neon. Hence two oxygen atoms combine by sharing two pairs of electrons between them and form a double bond. Similarly, nitrogen atom has five electrons in its outermost shell. It needs three electrons to complete its octet and attain the configuration of the inert gas neon. Hence, two nitrogen atoms combine by sharing three pairs of electrons between them and form a triple bond. In HCN molecule, H and C atoms share one pair of electron to form a single bond while C and N atoms share three pairs of electrons to form a triple bond.

13 Following figure shows the multiple bonds in O 2, N 2 and HCN molecules. 13 Figure 7 - Bonding in O 2, N 2 and HCN molecules. Activity 5 - Carbon atom has four electrons in its outermost shell. Oxygen atom has six electrons in its outermost shell. Arrange the valence electrons around these two atoms and draw the Lewis dot formula in such a way that each atom completes its octet. Name and count the types of bonds in the molecule. Polar and Non-polar covalent bonds There are two subtypes of covalent bonds non-polar and polar. The H 2 molecule is a good example of the first subtype of covalent bond. Since both atoms in H 2 molecule have an equal attraction ( or affinity ) for electrons, the bonding electrons are equally shared between the two atoms i.e. the shared pair lies exactly in the middle of two atoms and a non-polar covalent bond is formed. There is no charge separation and the molecule is non-polar. Whenever two atoms of the same element bond together, a non-polar covalent bond is formed. Following figure shows the non-polar covalent bond between H 2 and O 2 molecules. Figure 8 - Non-polar covalent bonds in H 2 and O 2 molecules

14 14 A polar covalent bond is formed when electrons are unequally shared between two atoms. Polar covalent bonding occurs because one atom has stronger affinity for electrons than the other ( yet not enough to pull the electrons away completely and form an ion).in a polar covalent bond, the bonding electrons spend more time around the atom that has the stronger affinity for electrons. Due to this uneven distribution of charge, one end of the molecule acquires a slightly positive charge while the other end acquires a slightly negative charge. These slight charges are represented by the symbols + and - (called delta). Good examples of polar covalent bond are HCl and H 2 O. The figure given below shows the polar covalent bond in HCl and H 2 O molecule. Figure 9 - Polar covalent bond in HCl and H 2 O molecules. The polar or non-polar nature of the covalent bond can be predicted from the electronegativity values of the two atoms. There is a correlation between the electronegativity difference and the percentage ionic character of the molecule. In case of HCl, the electronegativity difference between H and Cl is 0.9 and the ionic character is 20%. In case of NaCl molecule, the elctronegativity difference between Na and Cl is 2.1 and the ionic character is 65%. In order to have 50% ionic character in a molecule, the atoms should have 1.7 as the difference in electronegativity values. It is also possible that the multi-bond molecule is non-polar but the individual bonds in the molecule are polar. This is the case in carbon tetrachloride molecule. Each C Cl bond is slightly polar but the overall molecule is non-polar. When the directions of the bonds are taken into account, the net effect of the polarity of four C-Cl bonds is zero. Following figure shows the individual polarities of bond in carbon tetrachloride molecule. Figure 10 - Non-polar carbon tetrachloride molecule

15 Activity 6 - Draw the Lewis dot formula and show the polar covalent bond formation in HBr molecule. Coordinate bond 15 A coordinate bond, also known as dative or semi polar bond, is a special type of covalent bond in which the shared pair of electrons comes from one of the bonding atoms only. This bond is formed when an electron pair donor ( Lewis base ) donates a pair of electrons to an electron pair acceptor ( Lewis acid ) to give a so called adduct. The process of forming a coordinate bond is called coordination. In this process, the electron donor acquires a formal positive charge while the electron acceptor acquires a formal negative charge. Since a dipole is created, this bond is, sometimes, called as a dipolar bond. The distinction between a normal covalent bond and a coordinate bond is artificial. Once the coordinate bond is formed, its strength and description is no different from that of other polar covalent bond. Any atom, ion or molecule which has a lone pair of electrons is capable of forming a coordinate bond. For example, ammonia molecule has a lone pair of electrons. It can act as electron donor ( Lewis base). Hydrogen ion is electron deficient and can act as an electron acceptor ( Lewis acid ). When they come together, they form a coordinate bond. In this process, nitrogen of the ammonia molecule acquires a formal positive charge while hydrogen ion acquires a formal negative charge. Once the coordinate bond is formed all four N H bonds in ammonium ion become identical in all respects. The figure given below shows the formation of a coordinate bond between ammonia molecule and H + ion. Figure 11 - Formation of coordinate bond. Formation of H 3 O + ion and NH 3 BF 3 adduct are some more examples of coordinate bonding.

16 16 Characteristic Properties of Covalent Compounds Covalent compounds have following characteristic properties 1) Covalent compounds do not exist as ions but exist as molecules. They may occur in solid, liquid or gaseous state. 2) They are generally soft and have low melting and boiling points. 3) Covalent compounds are generally insoluble or less soluble in water and in other polar solvents. 4) Covalent compounds are poor conductors of electricity in fused or dissolved state. Check your understanding (i) Draw a potential energy curve for H 2 molecule and show the bond length and potential energy at which H 2 molecule is formed. (ii) What is the difference between covalent bond and coordinate bond? (iii) Choose the pairs of atoms which will form (i) non-polar (ii) polar covalent bond. Be, B, C, N, O, F, N, O, F (iv) Identify the types of bonds in NH 4 Cl molecule.

17 17 Concepts (i) Metallic bonding (ii) Characteristic properties of metals Metallic bonding The elements which are placed on the extreme left, the middle and a few on the right of the periodic table are metals. Alkali metals like sodium, potassium, alkaline earth metals like magnesium, calcium, transition metals like iron, cobalt, nickel, copper and others like lead, tin represent the family of metals. They have low electronegativity. They tend to lose their valence electrons easily. When we have a macroscopic collection of metal atoms, the valence electrons are detached from the atoms but not held by any of the other atoms. In other words, these valence electrons are free from any particular atom and are held only collectively by the entire assembly of atoms. When atoms lose their outer-shell electrons they become positive ions. The outer electrons become a sea of mobile electrons surrounding a lattice of positive ions. The positive ion cores are held more or less at fixed places in an ordered or crystal lattice. The valence electrons are free to move about under applied stimulation like electrical field or heat. This is called electron sea model of metals. The force of attraction which holds the delocalized (or mobile) electrons and the metallic nuclei together in a metal is called a metallic bond. Following figure shows electron sea model of metals. Figure 12 - Electron sea model of a metal

18 18 Although the term metallic bond is often used in contrast to the term covalent bond it is preferable to use the term metallic bonding because this type of bonding is collective in nature and a single metallic bond does not exist. Characteristic Properties of Metals Metals show following characteristic physical properties: 1) At room temperature, they are solids (except mercury) 2) They are opaque to light. 3) They, generally, have high density. 4) They show metallic luster. 5) They are malleable and ductile in their solid state. 6) They are good conductors of heat and electricity. 7) They have crystal structure in which each atom is surrounded by eight to twelve near neighbours. Activity 7 Draw the picture of a metal lattice and show the position of metal nuclei and valence electrons in the lattice. Activity 8 Metals generally have high densities. Support this statement by giving densities of some metals. Check your understanding (i) Why the crystal structure of metal is described as a sea of electrons? (ii) Give any one property of metals which can be explained by its crystal structure. Justify your answer.

19 19 Concepts (i) Hydrogen bond (ii) Effects of hydrogen bonding Hydrogen bond This is a different type of bond. It is restricted to only some molecules containing hydrogen atoms. The force of attraction between the hydrogen atom attached to an electronegative atom of one molecule and an electronegative atom of another molecule is called hydrogen bond. Usually, the electronegative atom is O, N or F. In a molecule, the O, N or F atom has a partial negative charge and then the hydrogen atom which has a very small size has a partial positive charge. This type of bond always involves hydrogen atom and hence the name hydrogen bond. In order to form a hydrogen bond, it is necessary that the electronegative atom should have one or more lone pairs of electrons and a partial negative charge so that there is a force of attraction termed as dipole-dipole interaction. The hydrogen atom which has a partial positive charge tries to find another atom of O,N or F with excess of electrons to share and is attracted to partial negative charge. This forms the basis of hydrogen bond. The hydrogen bond can occur between molecules ( intermolecular ) like HF or within different parts of a single molecule ( intramolecular ) like o-nitro phenol. The hydrogen bond is stronger than van-der-waals bond but weaker than covalent or ionic bond. The hydrogen bond has the bond energy in the range 5 to 30 kj per mole. Following figure shows hydrogen bonding in HF molecules. Figure 13 - Hydrogen bonding in HF

20 Activity 1 Draw the structure of water molecules with hydrogen bonding. Effects of hydrogen bonding Hydrogen bonding has effects on the properties of certain substances. 20 (i) Hydrogen bonding leads to association of molecules which affects the physical state of a substance. For example, HF which should be a gas at room temperature, becomes a liquid due to association of molecules. (ii) Covalent compounds are normally insoluble in water. But compounds like ethanol, lower aldehydes, ketones, though covalent, are soluble in water due to formation of hydrogen bonds with water molecules. (iii) The boiling points of water ( C), HF ( C) and ammonia ( C ) are exceptionally high as compared to other Group 16 hydrides which have no hydrogen bonds. (iv) Intramolecular hydrogen bonding is partly responsible for secondary, tertiary and quaternary structure of proteins and nucleic acids. It also plays an important role in the structure of polymers. Activity 2 - Draw the structure of o nitro phenol and show the intramolecular bonding in it. Check your understanding (i) Hydrogen bonding is known only in the hydrides of O, N and F. Why? (ii)water molecules are joined by hydrogen bonds. Is hydrogen bonding present in ice also?

21 21 References / Figures / Diagrams etc 1) Fig. 1 Periodic table and elements forming different types of bonds www. Smallscalechemistry.colostate.edu/ /chemicalbonding.pdf 2) Fig. 2 Combination of Na and Cl to form Na + and Cl - 3) Fig. 3 Potential energy diagram for NaCl molecule hbase/chemical/bond.html 4) Fig. 4 Potential energy diagram for H 2 molecule hbase/molecule/hmol.html 5) Fig. 5 Bonding in H 2 and Cl 2 molecule 6) Fig. 6 Bonding in H 2 O, NH 3 and CH 4 molecules 7) Fig.7 - Bonding in O 2, N 2 and HCN 8) Fig. 8 Non-polar covalent bond in H 2 and O 2 molecules For H 2 For O ) Fig. 9 Polar covalent bond in HCl and H 2 O molecules For H 2 O - For HCl 10) Fig. 10 Non-polar carbon tetrachloride molecule 11) Fig Formation of coordinate bond 12) Fig. 12 Electron sea model of a metal 13) Fig. 13 Hydrogen bonding in HF fluoride

22

Chapter No 4 Structure of molecules. Superior Lalazar Public School and College Thana.

Chapter No 4 Structure of molecules. Superior Lalazar Public School and College Thana. Chapter No 4 Structure of molecules Superior Lalazar Public School and College Thana www.slpsorg.com Chemical Bond: The force of attractions which holds atoms or ions together is called chemical bonds.

More information

Bonding. By: Mahmoud Taha Special thanks to Ms Williams and Ms Matrella for their constant support and inspiration

Bonding. By: Mahmoud Taha Special thanks to Ms Williams and Ms Matrella for their constant support and inspiration By: Mahmoud Taha Special thanks to Ms Williams and Ms Matrella for their constant support and inspiration Please note that these guides are a collation of my personal notes, teachers' notes, chemistry

More information

Question Bank Chemical Bonding

Question Bank Chemical Bonding Question Bank Chemical Bonding 1. Give one word/words for the statements given below : (a) Arrangement of electrons around the nucleus of an atom. [1] (b) A compound formed by the actual exchange of electrons

More information

*Hence, these elements react in order to achieve the noble gas configurations. This is made possible by any one of the three ways given below.

*Hence, these elements react in order to achieve the noble gas configurations. This is made possible by any one of the three ways given below. Chemical Bonding Noble gas configuration *Helium (He), neon (Ne) and argon (Ar) are some examples of the noble gases. They are found in Group 0 of the Periodic Table. *Noble gases exist as individual and

More information

Name: Date: Period: Guided Notes Chemical Bonding Part 1

Name: Date: Period: Guided Notes Chemical Bonding Part 1 Name: Date: Period: Guided Notes Chemical Bonding Part 1 Valence Electrons and Chemical Bonds A is the force that holds two atoms together. Chemical bonds form by the attraction between the positive nucleus

More information

Valence Electrons and Chemical Bonds

Valence Electrons and Chemical Bonds Valence Electrons and Chemical Bonds A chemical bond is the force that holds two atoms together. Chemical bonds form by the attraction between the positive nucleus of one atom and the negative electrons

More information

Topic 4. Chemical bonding and structure

Topic 4. Chemical bonding and structure Topic 4. Chemical bonding and structure There are three types of strong bonds: Ionic Covalent Metallic Some substances contain both covalent and ionic bonding or an intermediate. 4.1 Ionic bonding Ionic

More information

3s 2 3p 4. 2s 2 2p 1. Ionic Compounds. Chemical bonds. Lewis Electron-Dot Symbols

3s 2 3p 4. 2s 2 2p 1. Ionic Compounds. Chemical bonds. Lewis Electron-Dot Symbols Chemical bonds Chemical bond -- a strong attractive force between atoms that binds them together to form chemical compounds There are three classes of chemical bonds: Ionic bonds -- electrostatic forces

More information

Introduction to Ionic Bonds

Introduction to Ionic Bonds Introduction to Ionic Bonds The forces that hold matter together are called chemical bonds. There are four major types of bonds. We need to learn in detail about these bonds and how they influence the

More information

Chemical Bonding UNIT 4. Chapters 15 & 16

Chemical Bonding UNIT 4. Chapters 15 & 16 Chemical Bonding UNIT 4 Chapters 15 & 16 Ionic Bonding The bond in ionic compounds (two ions) Held together tightly High melting points Compounds are formed from chemically bound atoms or ions Substances

More information

X-ray diffraction: Electron density map of NaCl

X-ray diffraction: Electron density map of NaCl 4. Bonding Ionic Bonding Evidence for the existence of ions X-ray diffraction: Electron density map of NaCl These maps show the likelihood of finding electrons in a region The contours are lines of equal

More information

Bonding Two groups of bonds: Primary Bonds----Covalent Primary bonds consist of three types of bonds: ionic, covalent and metallic

Bonding Two groups of bonds: Primary Bonds----Covalent Primary bonds consist of three types of bonds: ionic, covalent and metallic Chemical Bonds Chemical bond is an attraction between atoms or molecules and allows the formation of chemical compounds, which contain two or more atoms. A bond is a link that binds 2 or more atoms of

More information

Page 1

Page 1 Atomic structure 1. What is an atom? An atom is the smallest unit of an element. 2. What is inside the atom? Subatomic particles - Protons, neutrons and electrons. 3. Where can you find these subatomic

More information

With this in mind, you are going to learn about how atoms combine to form new substances, and how the bonds between the atoms come about.

With this in mind, you are going to learn about how atoms combine to form new substances, and how the bonds between the atoms come about. 8.1-8.3 Introduction to Chemical Bonding In the unit on electron structure, it was clearly seen how the arrangement of electrons around the nucleus of the atom of an element can be deduced from the specific

More information

Models of Chemical Bonding

Models of Chemical Bonding Models of Chemical Bonding Bonds are forces holding atoms or ions together Bonds form as a result of lowering of the total energy (energy of separated species is higher than that of bonded species) 9.1

More information

Chemical Bonding. Introduction to Chemical Bonding

Chemical Bonding. Introduction to Chemical Bonding Chemical Bonding Introduction to Chemical Bonding Chemical Bonds A chemical bond is a mutual attraction between nuclei and valence electrons of different atoms that binds the atoms together. A chemical

More information

CHAPTER 6. Chemical Bonds

CHAPTER 6. Chemical Bonds CHAPTER 6 Chemical Bonds Valence Electrons 1. Electrons farthest away from the nucleus. The electrons in the highest occupied energy level of an atom of that element. 2. They play a key role in chemical

More information

Atom nucleus (protons and neutrons) electron cloud (electrons)

Atom nucleus (protons and neutrons) electron cloud (electrons) Atom nucleus (protons and neutrons) electron cloud (electrons) Atomic Number equal to the number of protons Mass Number protons + neutrons Charge when # of electrons # of protons Negatively Charged Ion

More information

CHAPTER 6 Chemical Bonding

CHAPTER 6 Chemical Bonding CHAPTER 6 Chemical Bonding SECTION 1 Introduction to Chemical Bonding OBJECTIVES 1. Define Chemical bond. 2. Explain why most atoms form chemical bonds. 3. Describe ionic and covalent bonding.. 4. Explain

More information

1. Which particles may be gained, lost, or shared by an atom when it forms a chemical bond? (1) protons (2) electrons (3) neutrons (4) nucleons

1. Which particles may be gained, lost, or shared by an atom when it forms a chemical bond? (1) protons (2) electrons (3) neutrons (4) nucleons Name: Bonding Review 1. Which particles may be gained, lost, or shared by an atom when it forms a chemical bond? (1) protons (2) electrons (3) neutrons (4) nucleons 2. As energy is released during the

More information

Easter School Physical Sciences Grade 11. Chemical Bonding 31 March 2013

Easter School Physical Sciences Grade 11. Chemical Bonding 31 March 2013 Key Concepts In this session we will focus on summarising what you need to know about: Bonding Covalent bonding Electronegativity in covalent bonding Shapes of molecules Polar covalent substances Bond

More information

Basic Concepts of Chemical Bonding

Basic Concepts of Chemical Bonding of Chemical Mr. Matthew Totaro Legacy High School AP Chemistry Chemical Bonds Three basic types of bonds Ionic Electrostatic attraction between ions. Covalent Sharing of electrons. Metallic Metal atoms

More information

Chapter 11. Chemical Bonds: The Formation of Compounds from Atoms

Chapter 11. Chemical Bonds: The Formation of Compounds from Atoms Chapter 11 Chemical Bonds: The Formation of Compounds from Atoms 1 11.1 Periodic Trends in atomic properties 11.1 Periodic Trends in atomic properties design of periodic table is based on observing properties

More information

Bonding Theories. Why Do Atoms Bond? Principles of Chemistry: Chapter 9 Chemical bonding. A Molecular Approach, 1 st Ed.

Bonding Theories. Why Do Atoms Bond? Principles of Chemistry: Chapter 9 Chemical bonding. A Molecular Approach, 1 st Ed. Principles of Chemistry: A Molecular Approach, 1 st Ed. Nivaldo Tro Chapter 9 Chemical bonding Bonding Theories Explain how and why atoms attach together why some combination of atoms are stable and others

More information

Chemical Bonds stable octet

Chemical Bonds stable octet Chemical Bonds Elements form bonds to be in a lower energy state 1. Ionic Bonds transfer of electrons, between metal and nonmetal 2. Covalent Bonds sharing of electrons, between two nonmetals 3. Metallic

More information

A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is called a(n)

A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is called a(n) Chemistry I ATOMIC BONDING PRACTICE QUIZ Mr. Scott Select the best answer. 1) A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is

More information

Chapter 8: Chemical Bonding and Climate Change

Chapter 8: Chemical Bonding and Climate Change Chapter 8: Chemical Bonding and Climate Change Problems: 8.1-8.58, 8.63-8.72, 8.77-8.79, 8.81-8.108, 8.111, 8.113-8.127, 8.129-8.135, 8.138, 8.140, 8.146 8.1 CHEMICAL BONDS chemical bond: what holds atoms

More information

Chapter -10 Chemical Bonding

Chapter -10 Chemical Bonding Chapter -10 Chemical Bonding Synopsis Atoms of elements which have the atoms are electrical neutral. All atoms have a tendency to attain the 8 electrons in their valency orbit as in noble gases. For this,

More information

Ionic vs. Covalent Compounds

Ionic vs. Covalent Compounds Ionic vs. Covalent Compounds 7 Electron Dot Diagrams American Chemist, G. N. Lewis (1916), developed a system of representing the valence electrons with dots Electron Dot Structures - Valence electrons

More information

Chemistry: Chapter 6

Chemistry: Chapter 6 Ellen Duong, Jake Macneal, Mikelanxhelo Novruzaj, Enxhi Rrapi, Weijia Wang Chemistry: Chapter 6 Vocabulary Chemical bond: mutual electrical attraction between nuclei and valence electrons of different

More information

CHEMICAL BONDING IONIC & METALLIC BONDS

CHEMICAL BONDING IONIC & METALLIC BONDS CHEMICAL BONDING IONIC & METALLIC BONDS Mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together When atoms form chemical bonds they have Lower

More information

Chemical Bonding and Nomenclature

Chemical Bonding and Nomenclature Chemical Bonding and Nomenclature Chemical Reactivity How much an element reacts depends on the electron configuration of its atoms. Every element wants 8 valence electrons. Oxygen only has six, so it

More information

Lecture Presentation. Chapter 9. Chemical Bonding I: The Lewis Model. Sherril Soman Grand Valley State University Pearson Education, Inc.

Lecture Presentation. Chapter 9. Chemical Bonding I: The Lewis Model. Sherril Soman Grand Valley State University Pearson Education, Inc. Lecture Presentation Chapter 9 Chemical Bonding I: The Lewis Model Sherril Soman Grand Valley State University HIV-Protease HIV-protease is a protein synthesized by the human immunodeficiency virus (HIV).

More information

Chapter 5 Notes: Ions and Ionic Compounds

Chapter 5 Notes: Ions and Ionic Compounds Chapter 5 Notes: Ions and Ionic Compounds Sec. 5.1 Simple Ions 1. Relate the electron configuration of an atom to its chemical reactivity. 2. Determine an atom s number of valence electrons, and use the

More information

... LED Li. Be. B. C . N : Name lithium beryllium boron carbon nitrogen oxygen fluorine neon. ... LED Na. Mg. Al. Si

... LED Li. Be. B. C . N : Name lithium beryllium boron carbon nitrogen oxygen fluorine neon. ... LED Na. Mg. Al. Si Chapter 5: Atoms, Bonding, and the Periodic Table Valence electrons and bonding Valence electrons electrons in the highest energy level (outermost electron shell) and are held most loosely The number of

More information

Section 8.3 Molecular Structures

Section 8.3 Molecular Structures Section 8.3 Molecular Structures List the basic steps used to draw Lewis structures. Explain why resonance occurs, and identify resonance structures. Identify three exceptions to the octet rule, and name

More information

The breaking of bonds and the forming of bonds occur during chemical reactions.

The breaking of bonds and the forming of bonds occur during chemical reactions. Chemical Bonding The breaking of bonds and the forming of bonds occur during chemical reactions. Aspirin The formula for a molecule of aspirin is C 9 H 8 O 4 Is it an ionic or covalent (molecular) compound?

More information

Chapters and 7.4 plus 8.1 and 8.3-5: Bonding, Solids, VSEPR, and Polarity

Chapters and 7.4 plus 8.1 and 8.3-5: Bonding, Solids, VSEPR, and Polarity Chapters 7.1-2 and 7.4 plus 8.1 and 8.3-5: Bonding, Solids, VSEPR, and Polarity Chemical Bonds and energy bond formation is always exothermic As bonds form, chemical potential energy is released as other

More information

2C Intermolecular forces, structure and properties:

2C Intermolecular forces, structure and properties: Electronegativity and polarity Polar and non-polar bonds: 1) Non-Polar bonds: 2C Intermolecular forces, structure and properties: A covalent bond shares an electron pair: In a hydrogen molecule, the electrons

More information

SESSION 7: CHEMICAL BONDING

SESSION 7: CHEMICAL BONDING SESSION 7: CHEMICAL BONDING KEY CONCEPTS: particles substances are made of types of chemical bonds models of chemical bonds identifying chemical bonds TERMINOLOGY Element A substance that cannot be broken

More information

Chapter 6, Section 6.1 Introduction to Chemical Bonding. Objectives. ii) Explain why most atoms form chemical bonds.

Chapter 6, Section 6.1 Introduction to Chemical Bonding. Objectives. ii) Explain why most atoms form chemical bonds. Chapter 6, Section 6.1 Introduction to Chemical Bonding i) Define chemical bond. Objectives ii) Explain why most atoms form chemical bonds. iii) Describe ionic and covalent bonding. iv) Explain why most

More information

Unit 3: Chemical Bonding

Unit 3: Chemical Bonding Unit 3: Chemical Bonding Listed below are the learning objectives that you will be taught. At the conclusion of each lesson, check one of the four boxes to indicate your level of understanding for each

More information

Name Date Class. octet rule halide ions

Name Date Class. octet rule halide ions 7.1 IONS Section Review Objectives Determine the number of valence electrons in an atom of a representative element Explain the octet rule Describe how cations form Explain how anions form Vocabulary valence

More information

Lecture 4. Lecture 4

Lecture 4. Lecture 4 Lecture 4 http://www.tcd.ie/chemistry/teaching/chemistry/jf/intro/intro.php Outline Lecture 4 Chemical Bonding 4.1 Law of conversation of mass 4.2 Law of definite composition 4.3 Bonding in chemical substances

More information

Chapter 7 Chemical Bonds

Chapter 7 Chemical Bonds Chapter 7 Chemical Bonds (A) Basic Concepts of Bonding 1. Define bonding. Bonding is a process in which an atom transfers electrons to, or shares electrons with, another atom in order to obtain the Octet

More information

Noble Gases are the most elements. Why? Notice that this makes a full outer energy level have electrons.

Noble Gases are the most elements. Why? Notice that this makes a full outer energy level have electrons. NAME: Mods: Now that we know proper formula writing and naming of chemical compounds so we can speak the language of Chemistry, let s move on to understanding how and why these compounds are put together!

More information

Covalent Bonding and Intermolecular Forces

Covalent Bonding and Intermolecular Forces Intermolecular forces are electromagnetic forces that hold like molecules together. Strong intermolecular forces result in a high melting point and a solid state at room temperature. Molecules that are

More information

Bonding Practice Problems

Bonding Practice Problems NAME 1. When compared to H 2 S, H 2 O has a higher 8. Given the Lewis electron-dot diagram: boiling point because H 2 O contains stronger metallic bonds covalent bonds ionic bonds hydrogen bonds 2. Which

More information

TOPIC 9 ANSWERS & MARK SCHEMES QUESTIONSHEET 1 BASIC CONCEPTS

TOPIC 9 ANSWERS & MARK SCHEMES QUESTIONSHEET 1 BASIC CONCEPTS QUESTIONSHEET 1 BASIC CONCEPTS a) (i) Increasing atomic number / number of protons (ii) Groups (iii) Periods b) (i) Alkali metals (ii) Alkaline earth metals (iii) Halogens (iv) Noble gases / inert gases

More information

GRADE 11 PHYSICAL SCIENCES SESSION 3: CHEMICAL BONDING. Key Concepts. X-planation

GRADE 11 PHYSICAL SCIENCES SESSION 3: CHEMICAL BONDING. Key Concepts. X-planation GRADE 11 PHYSICAL SCIENCES SESSION 3: CHEMICAL BONDING Key Concepts In this session we will focus on summarising what you need to know about: Bonding Covalent bonding Electronegativity in covalent bonding

More information

Chemical Bonding. Example with NaCl: You already know 2 types of bonding Ionic Covalent There are really 2 categories of bonding:

Chemical Bonding. Example with NaCl: You already know 2 types of bonding Ionic Covalent There are really 2 categories of bonding: Chemical Bonding You already know 2 types of bonding Ionic Covalent There are really 2 categories of bonding: 1) intramolecular (inside molecules) Ionic, covalent and polar covalent 2) intermolecular (between

More information

List the 3 main types of subatomic particles and indicate the mass and electrical charge of each.

List the 3 main types of subatomic particles and indicate the mass and electrical charge of each. Module 1C Basic Chemistry Chemistry the scientific study of the structure and properties of matter Why do we study chemistry in a biology course? All living organisms are composed of chemicals. To understand

More information

Unit Ionic and Covalent Bonds

Unit Ionic and Covalent Bonds Unit 6 --- Ionic and Covalent Bonds Electron Configuration in Ionic Bonding Ionic Bonds Bonding in Metals Valence Electrons Electrons in the highest occupied energy level of an element s atoms Examples

More information

1/13/2015. BONDING Notes

1/13/2015. BONDING Notes BONDING Notes Mr. Buchanan Introduction to Bonding Atoms are generally found in nature in combination held together by chemical bonds. A chemical bond is a mutual electrical attraction between the nuclei

More information

Lesmahagow High School CfE Higher Chemistry. Chemical Changes & Structure Structure and Bonding

Lesmahagow High School CfE Higher Chemistry. Chemical Changes & Structure Structure and Bonding Lesmahagow High School CfE Higher Chemistry Chemical Changes & Structure Structure and Bonding Page 1 of 26 No. Learning Outcome Understanding? 1 2 The bonding types of the first twenty elements; metallic

More information

Bonding. NaCl crystal lattice

Bonding. NaCl crystal lattice Bonding Atoms form bonds with one another because in doing so, they become more stable. Being usually stable means having a full octet of eight valence electrons. Atoms can achieve this full octet by either

More information

Section #2. Downloadable at:

Section #2. Downloadable at: Section #2 Downloadable at: http://tekim.undip.ac.id/staf/istadi 1 Compounds: Introduction to Bonding The noble gases - helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn) occur

More information

Ionic Compounds & Metals! Ion Formation!

Ionic Compounds & Metals! Ion Formation! Ionic Compounds & Metals! Ion Formation! Valence Electrons & Chemical Bonds! Main Idea: are formed when atoms gain or lose electrons to achieve a electron configuration.! Atoms gain or lose electrons to

More information

IPS Unit 9 Chemical Bonding and Formulas. Section 2

IPS Unit 9 Chemical Bonding and Formulas. Section 2 IPS Unit 9 Chemical Bonding and Formulas Section 2 Making Atoms Stable How does hydrogen, or any other element, become stable? They do this by combining with other atoms so that by gaining, losing, or

More information

Composition of Matter

Composition of Matter Matter The stuff that makes up the universe anything that takes up space States of matter Solid has definite shape and volume Liquid has definite volume, changeable shape Gas has changeable shape and volume

More information

Chapter 8. Basic Concepts of Chemical Bonding

Chapter 8. Basic Concepts of Chemical Bonding Chapter 8. Basic Concepts of Chemical Bonding Lecture Outline 8.1 Lewis Symbols and the Octet Rule The properties of many materials can be understood in terms of their microscopic properties. Microscopic

More information

Chapter 8: Concepts of Chemical Bonding

Chapter 8: Concepts of Chemical Bonding Chapter 8: Concepts of Chemical Bonding Learning Outcomes: Write Lewis symbols for atoms and ions. Define lattice energy and be able to arrange compounds in order of increasing lattice energy based on

More information

In the box below, draw the Lewis electron-dot structure for the compound formed from magnesium and oxygen. [Include any charges or partial charges.

In the box below, draw the Lewis electron-dot structure for the compound formed from magnesium and oxygen. [Include any charges or partial charges. Name: 1) Which molecule is nonpolar and has a symmetrical shape? A) NH3 B) H2O C) HCl D) CH4 7222-1 - Page 1 2) When ammonium chloride crystals are dissolved in water, the temperature of the water decreases.

More information

Chapter 6 Chemical Bonding

Chapter 6 Chemical Bonding Chapter 6 Chemical Bonding 6-1 Introduction to Chemical Bonding 1. A chemical bond is a mutual between the nuclei and electrons of different atoms that binds the atoms together. 2. By bonding with each

More information

MID-COURSE REVISION QUESTIONS

MID-COURSE REVISION QUESTIONS MID-COURSE REVISION QUESTIONS The following questions are designed both as revision and to allow you to assess your understanding of some of the concepts dealt with in Topics 1-8. They might be used in

More information

Molecular Geometry Part 1. David A. Katz Pima Community College Tucson, AZ

Molecular Geometry Part 1. David A. Katz Pima Community College Tucson, AZ Concepts of Chemical Bonding and Molecular Geometry Part 1 David A. Katz Pima Community College Tucson, AZ Chemical Bonds Three basic types of bonds: Ionic Electrostatic attraction between ions Covalent

More information

Ch. 4 Atoms and Bonding Outline

Ch. 4 Atoms and Bonding Outline Ch. 4 Atoms and Bonding Outline Lesson 1 A. Atoms bond to form compounds. This happens due to the behavior of the electrons of the atoms. 1. Electrons are found on different energy levels outside of an

More information

11 Chemical Bonds: The Formation of Compounds from Atoms

11 Chemical Bonds: The Formation of Compounds from Atoms 11 Chemical Bonds: The Formation of Compounds from Atoms Atoms in Vitamin C (ascorbic acid) bond in a specific orientation which defines the shape of the molecule. The molecules pack in a crystal, photographed

More information

Chapter 7. Chemical Bonding I: Basic Concepts

Chapter 7. Chemical Bonding I: Basic Concepts Chapter 7. Chemical Bonding I: Basic Concepts Chemical bond: is an attractive force that holds 2 atoms together and forms as a result of interactions between electrons found in combining atoms We rarely

More information

Wk 20&21 Ionic & Covalent Bonding.notebook. January 29, 2016

Wk 20&21 Ionic & Covalent Bonding.notebook. January 29, 2016 1/19 or 1/20/16 Wk 20 Bonding Objectives: SWBAT 7.1: Describe how oppositely charged particles attract to form neutral ionic compounds. IN: New Seating Chart & Notebook Requirements OUT: Be sure your notebook

More information

CHEMISTRY BONDING REVIEW

CHEMISTRY BONDING REVIEW Answer the following questions. CHEMISTRY BONDING REVIEW 1. What are the three kinds of bonds which can form between atoms? The three types of Bonds are Covalent, Ionic and Metallic. Name Date Block 2.

More information

5. 1 Covalent Bonds. Prentice Hall 2003 Chapter Five 1

5. 1 Covalent Bonds. Prentice Hall 2003 Chapter Five 1 5. 1 Covalent Bonds Covalent bond: : A bonds formed by sharing electrons between atoms. Molecule: A group of atoms held together by covalent bonds. The nonmetals near the middle of the periodic table reach

More information

CHEMICAL BONDS TYPES OF BONDS. UNIT 5: Bonding

CHEMICAL BONDS TYPES OF BONDS. UNIT 5: Bonding CEMICAL BONDS UNIT 5: Bonding A. Definition: A chemical bond is the force holding two atoms together in a chemical compound. B. Bonds form from the attraction 1. Between the positive nucleus of one atom

More information

Chemical Bonding Honors Chemistry Lesson

Chemical Bonding Honors Chemistry Lesson Chemical Bonding Honors Chemistry Lesson 12.15 Linus Pauling: Bonding: Measurement of force of attraction between 2 atoms. A bond has a lower potential energy than when separate. + 0 Valence electrons

More information

CHAPTER NOTES CHAPTER 16. Covalent Bonding

CHAPTER NOTES CHAPTER 16. Covalent Bonding CHAPTER NOTES CHAPTER 16 Covalent Bonding Goals : To gain an understanding of : NOTES: 1. Valence electron and electron dot notation. 2. Stable electron configurations. 3. Covalent bonding. 4. Polarity

More information

Chemical Bonds stable octet

Chemical Bonds stable octet Chemical Bonds Elements form bonds to be in a lower energy state 1. Ionic Bonds transfer of electrons, between metal and nonmetal 2. Covalent Bonds sharing of electrons, between two nonmetals 3. Metallic

More information

An Introduction to the Periodic Table

An Introduction to the Periodic Table An Introduction to the Periodic Table During the mid 1800 s, Russian scientist invented the modern periodic table after noticing a relationship between the and of the elements. He placed the elements in

More information

Chapter 7 Ionic and Metallic Bonding

Chapter 7 Ionic and Metallic Bonding Chapter 7 Ionic and Metallic Bonding Valence Electrons Scientists learned that all of the elements within each group of the periodic table behave similarly because they have the same number of valence

More information

Chapter # 5 CHEMICAL BONDING

Chapter # 5 CHEMICAL BONDING Chapter # 5 CHEMICAL BONDING You will learn in this chapter about: Why do atoms form chemical bonds? Ionic bond. Characteristics of ionic compounds. Covalent bond. Characteristic of covalent compounds.

More information

Chapter 11. Chemical Bonds: The Formation of Compounds from Atoms

Chapter 11. Chemical Bonds: The Formation of Compounds from Atoms Chapter 11 Chemical Bonds: The Formation of Compounds from Atoms The atoms in vitamin C (ascorbic acid) bond together in a very specific orientation to form the shape of the molecule. The molecules collect

More information

11 Chemical Bonds: The Formation of Compounds from Atoms. Chapter Outline. Periodic Trends in Atomic Properties. Periodic Trends in Atomic Properties

11 Chemical Bonds: The Formation of Compounds from Atoms. Chapter Outline. Periodic Trends in Atomic Properties. Periodic Trends in Atomic Properties 11 Chemical Bonds The Formation of Compounds from Atoms Chapter Outline 11.1 11.2 Lewis Structures of Atoms 11.3 The Ionic Bond Transfer of Electrons from One Atom to Another 11.4 Predicting Formulas of

More information

The Octet Rule and Bonding

The Octet Rule and Bonding Section 8 The Octet Rule and Bonding What Do You See? Learning Outcomes In this section you will Relate patterns in ionization energies of elements to patterns in their electron arrangements. Use your

More information

Ionic compounds and analysis. C2 Topic 2

Ionic compounds and analysis. C2 Topic 2 Ionic compounds and analysis C2 Topic 2 Why do atoms form bonds? Atoms of different elements can combine to form compounds by the formation of new chemical bonds Bonds involve the electrons in the outer

More information

Chapter 7 Chemical Bonding

Chapter 7 Chemical Bonding Chapter 7 Chemical Bonding 7.1 Ionic Bonding Octet rule: In forming compounds atoms lose, gain or share electrons to attain a noble gas configuration with 8 electrons in their outer shell (s 2 p 6 ), except

More information

Chemical Bonding. All Matter Exists as Atoms, Metals, Ions, or Molecules. All Matter Exists as Atoms,

Chemical Bonding. All Matter Exists as Atoms, Metals, Ions, or Molecules. All Matter Exists as Atoms, Chemical Bonding Review: Valence electrons (the outer most electrons) are responsible for the interaction between atoms when forming chemical compounds. Another way to say that is that valence electrons

More information

Matter, Elements, Compounds, Chemical Bonds and Energy

Matter, Elements, Compounds, Chemical Bonds and Energy Science of Kriyayoga IST 111-01, Spring 2005 Matter, Elements, Compounds, Chemical Bonds and Energy In our discussion so far, we have discussed human nervous system and cell biology, in addition to the

More information

Topic 3 National Chemistry Summary Notes. Bonding, Structure and Properties of Substances. Covalent Bonds

Topic 3 National Chemistry Summary Notes. Bonding, Structure and Properties of Substances. Covalent Bonds Topic 3 National Chemistry Summary Notes Bonding, Structure and Properties of Substances LI 1 Covalent Bonds Most atoms do not exist as single atoms. They are mainly found combined with other atoms in

More information

Lewis Theory Ionic bonding transfer Covalent bonding sharing ns2np6 octet rule

Lewis Theory Ionic bonding transfer Covalent bonding sharing ns2np6 octet rule Lewis Theory 1916-1919 - Lewis, Kossel, and Langmuir made several important proposals on bonding which lead to the development of Lewis Bonding Theory Elements of the theory: 1. Valence electrons play

More information

Type of Chemical Bonds

Type of Chemical Bonds Type of Chemical Bonds Covalent bond Polar Covalent bond Ionic bond Hydrogen bond Metallic bond Van der Waals bonds. Covalent Bonds Covalent bond: bond in which one or more pairs of electrons are shared

More information

Chpt 8 Bonding Genral Concepts. Bonding I

Chpt 8 Bonding Genral Concepts. Bonding I Chpt 8 Bonding Genral Concepts Bonding I Chemical Bonds The forces that hold a group of atoms together so that they can function as a group. Bond Energy The amount of energy needed to break a chemical

More information

When electrons are transferred from one atom to another it is called ionic bonding.

When electrons are transferred from one atom to another it is called ionic bonding. Ionic bonding The nature of the ionic bond When electrons are transferred from one atom to another it is called ionic bonding. Electronegativity is a property of an atom, describing how strongly it attracts

More information

NOTES:&&UNIT&5:& Bonding& & & & & & & & & & & & &

NOTES:&&UNIT&5:& Bonding& & & & & & & & & & & & & Name:&& & Regents&Chemistry:&Mr.&Palermo& & & & NOTES:&&UNIT&5:& Bonding& & & & & & & & & & & & & & & & & & & & www.mrpalermo.com& Name:&& & Key Ideas Compounds&can&be&differentiated&by&their&chemical&and&physical&properties.&(3.1dd)&

More information

SUPPLEMENTARY TOPIC 4 INTERMOLECULAR FORCES.

SUPPLEMENTARY TOPIC 4 INTERMOLECULAR FORCES. SUPPLEMENTARY TOPIC 4 INTERMOLECULAR FORCES. Previous Topics dealt with the strong bonding forces associated with ionic bonds, covalent bonds and metallic bonds. These forces are typically in the range

More information

Chapter 2 The Chemical Context of Life

Chapter 2 The Chemical Context of Life Chapter 2 The Chemical Context of Life Multiple-Choice Questions 1) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living

More information

Unit 2: Chemical Bonding. Chemistry2202

Unit 2: Chemical Bonding. Chemistry2202 Unit 2: Chemical Bonding Chemistry2202 Outline Bohr diagrams Lewis Diagrams Types of Bonding Ionic bonding Covalent bonding (Molecular) Metallic bonding Network covalent bonding Types of Bonding (cont

More information

Chapter 4: Structure and Properties of Ionic and Covalent Compounds

Chapter 4: Structure and Properties of Ionic and Covalent Compounds Chapter 4: Structure and Properties of Ionic and Covalent Compounds 4.1 Chemical Bonding o Chemical Bond - the force of attraction between any two atoms in a compound. o Interactions involving valence

More information

CHEMICAL BONDS. Chemical Bonds:

CHEMICAL BONDS. Chemical Bonds: CHEMICAL BONDS Chemical Bonds: The strong electrostatic forces of attraction holding atoms together in a unit are called chemical bonds (EU 2.C). Reflect a balance in the attractive and repulsive forces

More information

Chapter 8: Covalent Bonding

Chapter 8: Covalent Bonding Chapter 8: Covalent Bonding Section 8.1 Section 8.2 Section 8.3 Section 8.4 Section 8.5 The Covalent Bond Naming Molecules Molecular Structures Molecular Shapes Electronegativity and Polarity Review Vocabulary

More information

Chemical Bonding Chapter 11

Chemical Bonding Chapter 11 Chemical Bonding Chapter 11 Chemical Bond Lewis (1916): Not all the electrons in an atom participate in chemical bonding. Electrons occupy shells surrounding the nucleus: The inner shells Core electrons,

More information

Glossary: Bonding LESSON 9. a negatively charged ion. a positively charged ion

Glossary: Bonding LESSON 9. a negatively charged ion. a positively charged ion LESSON 9 Glossary: Bonding Anion Cation Covalent bond Double bond Electronegativity Ion Ionic bond Lewis electron-dot system Octet rule a negatively charged ion. a positively charged ion a chemical bond

More information