Unit 4, Part 1: Bonding - Student Notes of Chapters 5 & 6

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1 Ionic Bonding Octet Rule: When atoms react with each other they form or break. There are three different types of bonds:. I. Ionic Bonding results in the joining of 2 atoms by The two atoms stay together because The positive charge is created when The negative charge is created when The gives one or more electrons to the. An ionic compound is made of not molecules. Many ionic compounds are which is formed when a metal ion replaces the H atom in an acid. It is a solid with a crystalline structure and high melting point. The 2 elements involved in the ionic bond will have an An ionic compound is usually but not always made of a. Examples of ionic compounds Formula Chemical name Common name Cation Anion More properties ionic compounds have:

2 Lewis Structures for Ionic Compounds A uses Lewis dot diagrams to show how atoms are bonded in a compound. For writing a Lewis structure for an ionic compound: 1) Determine the for each atom in your compound using the periodic table. 2) Write a Lewis dot diagram for each atom in your compound. 3) Draw each electron that leaves the cation where it goes to form the anion. 4) Draw the. 5) Put around the and its electrons. 6) Put in the. Examples See the ones we did in class in your homework packet. Writing Formulae for Ionic Compounds Recall: A compound is formed when 2 or more atoms are attached together in a specific ratio by bonds. The for a compound is made of the of the elements in the compound and, small numbers written after the element to tell you how many of that type of atom is in the compound. Recall: You can use the location of the element in the periodic table to predict the charge of that element if it is a monatomic ion. A monatomic ion is Step 1) Determine. Use the periodic table or your polyatomic ion list to help you with this. The in the name of the ionic compound is your cation. If the cation is an element from the s or p block, or on your polyatomic ion sheet, look up the symbol & charge. If the cation is from the d or f block (or group 14), you will see a Roman numeral in the name, telling you the charge. Roman numerals are needed because There are two exceptions you need to know: silver = & zinc = 2

3 Step 2), bringing them down to form the subscripts and removing the positive or negative sign. Use parentheses around a polyatomic ion if you need more than 1. Step 3) if necessary. Atoms react to form neutral compounds in the simplest way possible. Examples: magnesium sulfide aluminum sulfate titanium(iv) oxide Naming Ionic Compounds Step 1) Determine where to split your compound. Look for polyatomic ions. Recall: A polyatomic ion is an. A monatomic ion is. Step 2) Name the (first). If it s from the, leave a set of blank after the name of the element. Step 3) Determine if the anion (second) is from the periodic table or a polyatomic ion. If it s a polyatomic, just name it. If it s monatomic, change the. Step 4) Fill in the with a Roman numeral to represent the. To do this first. Multiply the charge by the in the formula of cations. Roman Numeral Review: Examples: CuCl 2 NH 4 Br (NH 4 ) 3 PO 4 TiO 2 3

4 Covalent Bonding II. Covalent bond: The two atoms stay together because. The atoms are usually made of. A covalently bonded compound is called a. If the electrons are between the two atoms, the bond is. The electronegativity difference between the two atoms in the bond is. If the electrons are between the two atoms, the bond is. The electronegativity difference is. Examples of covalent compounds Formula Chemical name Common name More properties covalent compounds have: They can form multiple bonds between only 2 atoms. Single covalent bond is the sharing of Double covalent bond is the sharing of Triple covalent bond is the sharing of 8. In nature there are 7. They are never found as single atoms but always in pairs (di = 2) because they can bond with themselves to get an octet of valence electrons. Br 2 N 2 O 2 Cl 2 H 2 O 2 F 2 Lewis Structure for Covalent Compounds Step 1) Determine the number of all the valence electrons from all of the atoms. Step 2) Write for the atoms involved in the way they will be connected. The first element is usually. They are often written in the order they are connected. Step 3) Draw a between each pair of atoms bonded together. 4

5 Step 4) USE a PENCIL. of the atoms on the outside by drawing sets of two electrons unless it s hydrogen. You may run out of electrons. Step 5) Place any remaining electrons on the center atom. You might not always do this step. Step 6) If any atom does not meet its octet, by moving an unshared pair of electrons to the center atom. You will use your pencil eraser! Examples See the ones we did in class in your homework packet. Writing Formulae for Covalent Compounds Step 1) Determine the number of each atom you need by of each element. Prefixes for numbers 1 through 10: (similar to but not the same as your geometry ones) Step 2) Write the numbers as each element symbol. Examples: sulfur pentachloride diphosphorus hexachloride water ammonia Naming Covalent Compounds Step 1) Determine the number of atoms you have of each element and. Step 2) the first element placing the proper unless it s. Mono will never be used in the first name. Step 3) Name the second element placing the proper prefix in front.. Examples: CO 2 N 2 S 4 H 2 O NH 3 5

6 III. Metallic bond: is formed between. The valence electrons between the metal atoms. Those outer electrons are called. The free movement of electrons allows metals to be. IV. ACIDS: are a special set of compounds. They are but act when. The definition of acid we will use in this unit is an covalent compound that. NB: Water (H 2 O) is NOT an acid!!!!!!!!! Writing Formulae for acids Step 1) Determine the formula. Your cation will. If it starts with hydro,. If it doesn t start with hydro but ends with, find the matching polyatomic ion that ends with. If it doesn t start with hydro but ends with, find the matching polyatomic ion that ends with. Step 2) your charges. Examples: phosphoric acid phosphorous acid hydrophosphic acid Naming acids Step 1) Determine if the acid is: Binary or Ternary Step 2) If it s, add the prefix of the element after H. Name that element and. If it s you must. o If it ends in, change that to. o If it ends in, change that to. o (NB: NONE of these start with hydro!!!!!!!) Examples: HBr H 2 S H 2 SO 4 H 2 SO 3 6