Naming compounds and writing the formulas of compounds Sodium chloride NaCl Carbon dioxide CO 2 Copper(II) chloride CuCl 2

3 Sets of Rules for Naming Compounds Class or Type I - Ionic Bond between metal predictable + charge and a negative nonmetal or polyatomic ion ; name cations, anion ends in “ide” Examples: NaCl – sodium chloride ; MgCl 2, magnesium chloride Class or Type II- Ionic Bond with variable oxidation state transition metal; Roman numerals used to specify charge of transition metal Example: CuCl 2 – copper(II) chloride Class or Type III – Covalent bonds between Two nonmetals; uses prefixes Example: CO 2 – carbon dioxide; N 2 O 4 – dinitrogen tetroxide

Location of First Element in Formula determines class rules Class or Type I Class or Type II Class or Type III

Location of First Element in Formula determines class rules Class or Type I Class or Type II Class or Type III

Location of First Element in Formula determines class rules Class or Type I Class or Type II Class or Type III

Homework 2-4 SnBr 4 ___ AlH 3 ___ FeO ___ OF 2 ___ XeF 6 ___ Ca 3 N 2 ___ CBr 4 ____ MnF 2 ____ Lithium oxide ____ diboron hexachloride ___ Copper(I) hydroxide ___ barium nitrate ___ Cobalt(II) sulfate ____ sulfur dioxide ____

Homework 2-4 SnBr 4 ___ AlH 3 ___ FeO ___ OF 2 ___ XeF 6 ___ Ca 3 N 2 ___ CBr 4 ____ MnF 2 ____ Lithium oxide ____ diboron hexachloride ___ Copper(I) hydroxide ___ barium nitrate ___ Cobalt(II) sulfate ____ sulfur dioxide ____

What patterns in charges do you notice? What is different about the teal elements?

Class or Type I Compounds Class or Type I - Ionic Bond between metal with a predictable + charge and a negative nonmetal or polyatomic ion Rules for Naming Class or Type I Compounds Name metal cation (positive + ion) first using element name; Name nonmetal anion (negative – ion 2nd); change element name of anion to ends in “ide” Example #1: NaCl = elements: sodium and chlorine ; Change chlorine → chloride Ans: sodium chloride Example #2: MgCl 2 magnesium chloride

Practice - Name the following compounds: AlCl 3 ZnBr 2 Ga 2 O 3 aluminum chloride zinc bromide gallium oxide

Writing Formulas for Class I Compounds Use location on periodic table to find charge for each element Sum of charges must be zero. If + charge ≠ - charge, use “Criss-Cross” technique Final subscripts must be simplest ratio.

Example #1: (+ charge on cation = - charge on anion) What is the formula of potassium bromide? K = group 1 = lose 1 valence e- to fill outer level → +1 ion Br = Group 7 = gain 1 valence e- to fill outer level → -1 ion

What is the formula of potassium bromide? + → [K] + Charges must balance in final formula. K +1 + Br -1 → KBr

Example #2: (+ charge on cation = - charge on anion) What is the formula of calcium nitride? Ca = group 2 = lose 2 valence e- to fill outer level → +2 ion Br = Group 5 = gain 3 valence e- to fill outer level → -3 ion

What is the formula of calcium nitride? Charges: Ca +2 N -3 Criss-Cross move charge # (ignore + or – ) to subscript on opposite ion Ca +2 N -3 Final Answer: Ca 3 N 2

Practice- write formulas for the following compounds Magnesium sulfide Mg +2 S -2 → MgS (simplest ratio) Aluminum oxide Al +3 O -2 → Al 2 O 3 Potassium sulfide K +1 S -2 → K 2 S