Chemistry 11
Compounds and
Formulas
by: Justin Pouliot
Monovalent Compounds
- metals with single ionic charge
1.
2.
3.
4.
^= superscript
name each element
*= subscript
identify combining capacities
criss cross charges
put symbols together and write down subscripts or for
formulas write each element name down
Tips: + and - charges of same numerical value cancel each
other out, remove combining capacity symbol
Ex. Beryllium fluoride
BeF*2
Be^2 F^-1
Beryllium fluoride
BeF*2
Multivalent Compounds
- metal with more than one possible ionic charge
1. identify metal
2. identify combining capacities
3. look at formula to find metals combining capacities
4. criss cross combing capacities
5. write combining capacity of metal in brackets
6. change nonmetal ending to ide
Hints: Steps 5 and 6 do not apply for naming of compounds
from formula to compound.
Ex. Iron (III) oxide
PbO*2
Fe^3 O^-2
Lead (II) oxide
Polyatomic Compounds
- atoms bounded with charges and contain polyatomic ions
1. Identify metal or NH*4 (ammonium)
2. indicate multivalent combining capacity in brackets (for
compound to formula only)
3. identify polyatomic ion from list on Periodic Table
4. criss cross combing capacities (formula to compound
only)
Ex. NaSO*4
Lead(IV)carbonate
Sodium^1 Sulphate^-2
Pb^4 (CO*3)*-2
Sodium Sulphate
Pb*2(CO*3)*4
No brackets needed because sodium did not have
multivalent ion charges.
Hydrates
- solid compound surrounded by water molecules
1. name compound
2. write prefix in front of hydrate (compound to formula
only)
3. write equivalent prefix in front of H*20 (formula to
compound only)
Ex. NiSo*4 6H*20
Copper(II) sulfate pentahydrate
Nickel(II) sulfate hexahydrate CuSO*4 5H*20
Prefix: mono di tri tetra penta hexa hepta octa nona deca
Value:
1 2 3 4
5
6
7
8
9
10
Binary Compounds
- 2 atoms in a covalent compound
1.
2.
3.
4.
Identify elements
Identify subscript value (compound to formula)
Identify prefixes (formula to compound)
write name of elements with corresponding prefixes in
front (compound to formula only)
5. write symbol of element and write prefixes as numerical
subscripts
Ex. N*4 O*6
Dinitrogen monoxide
Tetranitrogen hexaoxide N*2 O
Hints: prefix mono becomes mon in front of elements
starting with O, do not add prefix to atoms with