Chapter 5 Naming Compounds Writing Formulas. Naming Binary Ionic Compounds l Binary Compounds - 2 elements. l Ionic - a cation and an anion. l To write.

Chapter 5

Naming Compounds

Writing Formulas

Naming Binary Ionic Compounds Binary Compounds - 2 elements. Ionic - a cation and an anion. To write the names just name the two

ions. Easy with Representative elements. Group A NaCl = Na+ Cl- = sodium chloride

MgBr2 = Mg+2 Br- = magnesium bromide

Naming Binary Ionic Compounds The problem comes with the transition

metals. Need to figure out their charges. The compound must be neutral. same number of + and – charges. Use the anion to determine the charge

on the positive ion.

Naming Binary Ionic Compounds Write the name of CuO Need the charge of Cu O is -2 copper must be +2 Copper (II) chloride Name CoCl3

Cl is -1 and there are three of them = -3 Co must be +3 Cobalt (III) chloride

Naming Binary Ionic Compounds Write the name of Cu2S. Since S is -2, the Cu2 must be +2, so

each one is +1. copper (I) sulfide Fe2O3 Each O is -2 3 x -2 = -6 2 Fe must = +6, so each is +3. iron (III) oxide

Naming Binary Ionic Compounds Write the names of the following KCl Na3N

CrN

Sc3P2

PbO

PbO2

Na2Se

Ternary Ionic Compounds Will have polyatomic ions At least three elements Just write the name of the element using the

front of the periodic table and the polyatomic ion using the chart on the back of the table.

Examples of naming ternary ionic compounds:

NaNO3 = sodium nitrate (NH4)2O = ammonium oxide

Ternary Ionic Compoundsname these:

LiCN Fe(OH)3

(NH4)2CO3

NiPO4

CaSO4

CuSO3

Writing Formulas The charges have to add up to zero. Get charges for the 2 parts. Cations from location on p. table. Anions from p. table or polyatomic. Balance the charges by putting in

subscripts (small #’s on bottom right). Put polyatomic ions in parenthesis

before you give them subscripts.

Writing Formulas Write the formula for calcium chloride. Calcium is Ca+2 Chloride is Cl-1 Ca+2 Cl-1 would have a +1 charge. Need another Cl-1 Ca+2 Cl2

-1

CaCl2

Write the formulas for these Lithium sulfide tin (II) oxide tin (IV) oxide Magnesium fluoride Copper (II) sulfate Iron (III) phosphide gallium nitrate Iron (III) sulfide

Write the formulas for these Ammonium chloride ammonium sulfide barium nitrate

Things to look for If cations have (roman numeral), the

number is their charge. If anions end in -ide they are probably

off the periodic table (Monoatomic) Exceptions (Hydroxide (OH); Cyanide (CN)

are polyatomic. If anion ends in -ate or -ite it is

polyatomic.

Molecular Compounds

Writing names and Formulas

Molecular compounds made of just nonmetals smallest piece is a molecule can’t be held together because of

opposite charges can’t use charges to figure out how

many of each atom

Easier Ionic compounds use charges to

determine how many of each.

– Have to figure out charges.

– Have to figure out numbers. Molecular compounds name tells you

the kind of atoms. Uses prefixes to tell you the number

Prefixes 1 mono- 2 di- 3 tri- 4 tetra- 5 penta-

6 hexa-•7 hepta-•8 octa- •9 nona-•10 deca-

Prefixes To write the name write two words

Prefix name Prefix name -ide

Prefixes To write the name write two words

One exception is we don’t write mono- if there is only one of the first element.

Prefix name Prefix name -ide

Prefixes To write the name write two words

One exception is we don’t write mono- if there is only one of the first element.

No double vowels when writing names (oa oo)

Prefix name Prefix name -ide

Name These N2O

NO2

Cl2O7

CBr4

BaCl2

Ex. CO carbon monoxide

CO2 carbon dioxide

P2O5 diphosphorus pentoxide

Write formulas for these diphosphorus pentoxide tetraiodide nonoxide sulfur hexaflouride nitrogen trioxide Carbon tetrahydride phosphorus trifluoride aluminum chloride

Acids

Writing names and Formulas

Acids Compounds that give off hydrogen ions

when dissolved in water. Must have H in them. will always be some H next to an anion. The anion determines the name.

Naming acids If the anion attached to hydrogen is

ends in -ide, put the prefix hydro- and change -ide to -ic acid

HCl - hydrogen ion and chloride ion hydrochloric acid H2S hydrogen ion and sulfide ion hydrosulfuric acid

Naming Acids If the anion has oxygen in it it ends in -ate or -ite change the suffix -ate to -ic acid HNO3 Hydrogen and nitrate ions

Nitric acid change the suffix -ite to -ous acid HNO2 Hydrogen and nitrite ions

Nitrous acid

Name these HF H3P

H2SO4

H2SO3

HCN H2CrO4

Writing Acid Formulas/Naming Hydrogen will always be first name will tell you the anion make the charges cancel out Starts with hydro- if no oxygen in the acid, -ide

ending becomes –icEx. HCl = hydochloric acid

no hydro, -ate ending from polyatomic ion becomes -ic, H2SO4 = sulfuric acid

-ite ending becomes –ous, H2SO3 = sulfurous acid

Write formulas for these hydroiodic acid acetic acid carbonic acid phosphorous acid hydrobromic acid