and sulfur express as a chemical formula (use subscripts to

represent the number of each type of atom or ion in a

molecule.

## Answer

Steps to follow:

1. Write the symbols for the cation and the anion: K for

potassium and S for sulfur.

2. Determine the charge on the cation and anion:

Potassium (K) belongs to group 1 so it has a charge of +1,

K^{+}. Sulfur is in group 16 so it has a charge of -2,

S^{2-}.

3. Determine formula. Write the two symbols together and

determine how to make the compound neutral by finding the lowest

common multiple of the charges on each ion. Then figure out how

atoms of each element are needed to make that charge.

K^{+} S^{2-}. The lowest common multiple is two.

To get a charge of two on potassium, you multiply it by 2 -(2 * 1 =

2). So, two potassium. To get a charge of two on sulfur, which has

a -2 charge, you need to multiply it by one – (1 * 2 = 2). So you

will have one sulfur ion.

Therefore, the formula becomes: K_{2}S.