Answer
Name: Potassium Sulfide
Formula: K$_{2}$S
Work Step by Step
Potassium wants to get rid of 1 electron, Sulfur wants 2 electrons, therefore two ions are formed. K$^{+}$ and S$^{2-}$, hence you need 2 potassium ions for every one sulfur ion to keep the molecule neutral, therefore the formula is K$_{2}$S. When naming ionic compounds, the positively charged ion keeps its name and the negatively charged ion has its ending dropped and replaced with -ide. Hence, the name is Potassium Sulfide.