Question

part 2
remember the standard format for writing the formula of an ionic compound.
although nonmetals may bond in different combinations, there is only one combination of a particular pair of ions that results in a neutral compound.
when forming a monatomic ion, k will electron(s), while s will electron(s).
the formula for potassium sulfide is therefore

Explanation:

Step1: Determine ion - formation of K

Potassium (K) is in Group 1 of the periodic table. It has 1 valence electron and will lose 1 electron to form a $K^{+}$ ion.

Step2: Determine ion - formation of S

Sulfur (S) is in Group 16 of the periodic table. It has 6 valence electrons and will gain 2 electrons to form a $S^{2 - }$ ion.

Step3: Write the formula of potassium sulfide

To form a neutral compound, we need 2 potassium ions for every 1 sulfide ion. So the formula is $K_{2}S$.

Answer:

When forming a monatomic ion, K will lose 1 electron(s), while S will gain 2 electron(s). The formula for potassium sulfide is $K_{2}S$.