WS17/ HW17 NAME: Chapter 13 Chemical Bonding 13.1 (Pg. 367) Electrons and Chemical Bonding 2. Which of the following atoms do not usually form bonds? a. calcium b. neon c. hydrogen d. oxygen 4. Explain how to use the valence electrons in an atom to predict if the atom will form bonds. 5. How can an atom that has 5 valence electrons achieve a full set of valence electrons? 6. Identify the number of valence electrons in a barium atom. 7. Look at the model below. How many valence electrons are in a fluorine atom? Will fluorine atoms form bonds? Explain. 13.2 (Pg. 371) Ionic Bonds 3. Which types of atoms usually become negative ions? a. metals b. nonmetals c. noble gases d. All of the above 4. How does an atom become a positive ion? a negative ion? 5. What are two properties of ionic compounds? 6. What is the charge of an ion that has 12 protons and 10 electrons? Write the ion s symbol. Show your work below. 1
7. Which group of elements gains two valence electrons when the atoms form ionic bonds? 8. Explain why ionic compounds are neutral even though they are made up of charged particles. 9. Compare the formation of positive ions with the formation of negative ions in terms of energy changes. 13.3 (Pg. 377) Covalent and Metallic Bonds 2. In your own words, write a definition for the term molecule. 3. Between which of the following atoms is a covalent bond most likely to occur? a. calcium and lithium b. sodium and fluorine c. nitrogen and oxygen d. helium and argon 4. What happens to the electrons in covalent bonding? 5. How many dots does an electron-dot diagram of a sulfur atom have? 6. List three properties of metals that are a result of metallic bonds. 7. Describe how the valence electrons in a metal move. 8. Explain the difference between ductility and malleability. Give an example of when each property is useful. 9. How do the metallic bonds in a staple allow it to function properly? 10. Draw an electron-dot diagram for ammonia (a nitrogen atom covalently bonded to three hydrogen atoms). 11. This electron-dot diagram is not complete. Which atom needs to form another bond? Explain. 2
Chapter Review Complete each of the following sentences by choosing the correct term from the word bank. crystal lattice ionic bond molecule chemical bond covalent bond chemical bonding metallic bond valence electron ion 1. An interaction that holds two atoms together is a(n). 2. A charged particle that forms when an atom transfers electrons is a(n). 3. A bond formed when atoms share electrons is a(n). 4. Electrons free to move throughout a material are associated with a(n). 5. An electron in the outermost energy level of an atom is a(n). 6. Ionic compounds are bonded in a three-dimensional pattern called a(n). 13. Explain why an iron ion is attracted to a sulfide ion but not to a zinc ion. 15. For each atom below, write the number of electrons it must gain or lose to have 8 valence electrons. Then, calculate the charge of the ion that would form. Show your work below. a. calcium, Ca b. phosphorus, P c. bromine, Br d. sulfur, S [gain/lose] electrons [gain/lose] electrons [gain/lose] electrons [gain/lose] electrons Ion charge = Ion charge = Ion charge = Ion charge = 17. Predict the type of bond each of the following pairs of atoms would form: a. zinc, Zn, and zinc, Zn b. oxygen, O, and c. phosphorus, P, and nitrogen, N oxygen, O d. magnesium, Mg, and chlorine, Cl 18. Applying Concepts Draw electron-dot diagrams for each of the following atoms, and state how many bonds it will have to make to fill its outer energy level. a. sulfur, S b. nitrogen, N c. neon, Ne How many bonds? d. iodine, I How many bonds? e. silicon, Si How many bonds? How many bonds? How many bonds? 19. Predicting Consequences Using your knowledge of valence electrons, explain the main reason so many different molecules are made from carbon atoms. 3
Is It an Ion? Answer the following questions based on the accompanying models. Protons are shown in gray, neutrons are shown in white, and electrons are shown in black. Answer Questions 1 6 based on Figure 1. 1. How many protons are shown? 2. In the periodic table, elements are ordered by atomic number, the number of protons in an atom s nucleus. Using the periodic table in your textbook, identify the element shown. 3. How many electrons are shown? 4. How many electrons are in the outermost energy level? 5. If the number of electrons equals the number of protons, then there is no charge, and the model shows a neutral atom. If the numbers are not equal, then you have an ion. Use this reasoning to determine if Figure 1 shows an ion or a neutral atom. 6. To determine a particle s charge, you must compare the number of protons with the number of electrons. Use the spaces to the right to subtract the number of electrons from the number of protons. (Remember, if the number of electrons is greater than the number of protons, the charge will be negative.) Answer Questions 7 11 based on Figure 2. 7. How many protons are shown? 8. What element is it? 9. How many electrons are shown? 10. How many electrons are in the outermost energy level? 11. Is this an ion? If it is, calculate and record the charge. Interview With an Electron Complete this worksheet after you finish reading the section Covalent and Metallic Bonds. The following descriptions are from the point of view of electrons that are participating in three different types of bonds ionic, metallic, and covalent. Identify the type of bond that each electron describes. At the bottom of the page is a list of characteristics of bonds and substances containing the bonds. Match each characteristic with the corresponding bond, and write the characteristic in the space provided. 1. My buddies and I do not feel bound to the energy level of one atom in particular, so we can swim freely throughout the substance. Type of bond: Characteristics: 4
2. I might change sides at the start, but once I end up on one side or the other I stick to my decision. Type of bond: Characteristics: 3. I do not feel partial to either of the atoms in my bond. To be fair, the other bonding electron and I divide our time between the bonded atoms. Type of bond: Characteristics: CHARACTERISTICS There s a transfer of electrons. Two or more nonmetals are involved. There s an attraction between positive ions and free-moving electrons. A metal reacts with a nonmetal. Compounds have a crystal-lattice structure. Substances are good conductors of electric current. There s an attraction between nuclei and shared electrons. Study Guide: Chapter 13 Chemical Bonding 13.1 Electrons and Chemical Bonds Q Chemical Bond Q Valence electron Q Groups and Valence electrons G1: G13: G15: G17: G2: G14: G16: G18: Q How many valence electrons? Radium (Ra is in G ) iodine (I is in G ) Cesium (Cs is in G ) Lead (Pb is in G ) neon (Ne is in G ) Q An energy level is considered full with valence electrons. Why are alkali metals very reactive? 5
Why are the alkaline-earth metals very reactive? Why are the halogens very reactive? Why are the noble gases unreactive? Q Draw the Bohr model for each element Magnesium Neon Aluminum Sulfur Argon 13.2 Ionic Bonds Q Q Draw table salt NaCl (Sodium Chloride) Q Forming Positive Ions: Lose electron charge Metals tend to electrons. (Groups ) Metal atoms tend to become ions. Atom needs to energy to pull away an electron. Q Forming Negative Ions (-ide): gain electron charge. Nonmetal atoms outermost orbital.(groups ) Nonmetals tend to electrons. Atom tends to energy to gain electron. 6
Q Ionic Compound = The compound has charge. Properties: Q How does an atom develop charge? Q What is a crystal lattice? Q Draw the Ions Sulfide Ion Symbol Charges protons electrons -------------------------- charge Aluminum Ion Symbol Charges protons electrons -------------------------- charge Oxide Ion Symbol Charges protons electrons -------------------------- charge Q Draw the Ionic Compound Sodium-Fluoride (found in toothpaste) Q Covalent Bond = 13.3 Covalent and Metallic Bonds Q Electron-dot diagram = 7
Q Draw the electron-dot diagrams for Carbon Oxygen Krypton Q Hydrogen is a diatomic element. Draw the hydrogen molecule. Q Draw the water molecule. Q Draw these covalently bonded molecules Bohr Model Ammonia NH 3 Bohr Model Methane CH 4 Bohr Model Hydrogen Sulfide H 2 S Electron-dot diagram Electron-dot diagram Electron-dot diagram Toothpick model Toothpick model Toothpick model Q Double and Triple Bonds Oxygen O 2 Carbon Dioxide CO 2 Nitrogen N 2 8