Writing SymbolsMG or Mg or mg

All symbols are written with a capital letter first.

• If it is a one letter symbol it is capital• If it is a two letter symbol first is capital,

second letter is lowercase

Mg O Ni Co N Cs K Be

Counting Atoms

The number of atoms is written as a subscript

AlCl3 = 1 aluminum, and 3 chlorine

Na2O = 2 sodium, and 1 oxygen

1 is never written and is always understood

Counting Atoms

3Li2O = 6 Lithium and 3 Oxygen.

A number in front must be distributed through the entire compound.

6C6H12O6 = 36 Carbons, 72 Hydrogens, 36 Oxygens

Counting Atoms

Pb(OH)2 = 1 Lead, 2 Oxygen, 2 Hydrogen

In parenthesis the subscript indicates the number of everything in the parenthesis and therefore must be distributed through.

Al2(SO4)3 = 2 Aluminum, 3 Sulfur, 12 Oxygen

Counting Atoms

NH4NO3 = 2 Nitrogen, 4 Hydrogen, 3 Oxygen

If an element appears in two different places it must be added together and totaled.

2H3C6H5O7 = 12 Carbon, 14 Oxygen, 16 Hydrogen

Practice1.    KOH 2.    Hg(OH)

3.    FeCl3 4.    NH4OH

5.    CCl4 6.    Pb(OH) 2

7.    NH4NO3 8.    Al2(SO4) 3

9.    Li2O 10.  Na2SO3

• 2H2 12. 2NaCl

13. 6H2O 14.   3C2H6

15.   2Al2O3 16.   4AgNO3

17.   5C2H6O 18.   H3C6H5O7

19.   2Ga(OH)320. 3Pb(NO3)2