Chemical Formula and Naming

• Write formulas and names for polyatomic compounds.

Additional KEY Terms

Octet rule: atoms react to get a full outer shell

Ionic Compound:

Ions are atoms that have reacted to gain or lose electrons

Lose e- – positive ion OR cation. (metals)Gain e- – negative ion OR anion. (nonmetals)

• Bonding of two oppositely charged IONS.

calcium chlorideIron (II) chloride

Fe Cl + -12

FeCl2

Ca Cl + -12

CaCl2

PbO

Pb O+ -1

2

lead oxide(IV)

+4 -2

Covalent Compound:

• Contain two or more NON-METAL atoms.• Molecule is smallest unit of covalent compound.

Formed by SHARING valence electrons:

Equally shared electrons – non-polar covalentUnequally shared electrons – polar covalent

Prefix Number of Atoms

mono 1di 2tri 3

tetra 4penta 5hexa 6hepta 7octa 8nona 9deca 10

nitrogen oxide

N O

di

2 4

tetradinitrogen tetroxide

PrefixNumber of

Atoms

mono 1

di 2

tri 3

tetra 4

penta 5

hexa 6

phosphorus oxide

P O di

2 5

penta

Polyatomic Ions (poly = many)

Groups of covalently bonded atoms that act as ions.

Polyatomic ions function as one unit with one charge – lose or gain electrons.

NEVER change the subscripts of polyatomic ions.

Al(C2H3O2)3

Write the name of the ionic compound:

Al(C2H3O2)

Al C2H3O2

+ - 1

3

aluminum acetate

nickel (II) nitrate

MgSO4

potassium permanganate

Fe(OH)3

calcium acetate

Ag2CrO4

lead (II) carbonate

Sn(SO4)2

sodium hydrogen phosphate

NH4NO2

1. Ni(NO3)2

2. magnesium sulfate

3. KMnO4

4. iron (III) hydroxide

5. Ca(C2H3O2)2

6. silver chromate

7. PbCO3

8. tin (IV) sulfate

9. Na2HPO4

10.ammonium nitrite

CAN YOU / HAVE YOU?

• Write formulas and names for polyatomic compounds.

Additional KEY Terms