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Chapter 9Chemical Names and Formulas

9.1 Naming Ions

9.2 Naming and Writing Formulas for Ionic Compounds

9.3 Naming and Writing Formulas for Molecular Compounds

9.4 Naming and Writing Formulas forAcids and Bases

9.5 The Laws Governing How Compounds Form

Naming Ions

• Monoatomic ion – one atom with charge• Ion – atom with chargeo cation- metals, location: left of periodic

table, positive chargeo anion – nonmetals, right of table, negative

charge

Predicting Ionic ChargesGroup 1A: Lose 1 electron to form 1+ ions

H1+ Li1+ Na1+ K1+ Rb1+

Predicting Ionic Charges

• The charge is sometimes referred to as the oxidation number or oxidation state

Chemical names and Formulas

• There are three types of ionic compounds to write formulas for and nameo Binary ionic compoundo Transition metal compoundo Ionic compound containing polyatomic ions

• Covalent compounds have a different naming system

It uses prefixes• Acids

Chemical names and Formulas

• Binary ionic compounds are made up of only 2 different elements

o There can be more than 2 or more atoms

though

NaCl K2O Al2S3

• To name a binary ionic compound Write the name of the cation first (always a

metal) Write the name of the anion, but change the

ending to –ide Note that any subscripts do not change the name

NaClsodiumchlorine → chloridesodium chloride

Chemical Naming

K2O

Al2S3

Name the following compounds KI

MgO

SrS

BeF2

Li2O

Al2O3

Cs3N

Ba3P2

Worksheet

Writing Chemical Formulas

• To write formulas it is important to remember that the charges on the compound must be balancedo Same total number of positive and negative charges

• Determine if the charges are balanced NaCl LiO KI BeBr NaBr

• When charges are not balanced, it is necessary to add subscripts o They represent the quantity of each elemento No subscript equals 1 atom

• Li+O2- the charges are not equalo There is only one positive and two negativeso We need another positive charge to make them equalo Li2O

• Write formulas for the following compoundso Sodium sulfideo Potassium iodideo Calcium bromideo Aluminum oxideo Boron bromideo Rubidium selenide

Writing Formulas for transition metals

• Sometimes the metal in a compound is a transition metal

• Transition metals can have various oxidation numbers or charges

• For example iron can be either Fe2+ or Fe3+

• Polyatomic ions are ions that contain more than one atom

o (SO4)2-

o (OH)-

o (PO4)3-

o (NH4)+

• It is important to note that the charge is distributed throughout all the atoms in the iono Not only on the last atom