Question #3651d

Mar 1, 2016

Potassium chromate.

Explanation:

The important thing to realize here is that you're dealing with an ionic compound, which implies that you're going to have to make sure that you identify the cation and the anion correctly.

Start with the cation, which in your case is the potassium cation. Since potassium is located in group 1 of the periodic table, it will form $1 +$ cations.

This means that the potassium cation carries a $1 +$ charge, ${\text{K}}^{+}$.

Notice that the formula contains two potassium cations. This tells you that the charge of the anion must be equal to $2 -$.

Remember, ionic compounds are neutral, which means that the overall positive charge coming from the cations must be balanced by the overall negative charge coming from the anions.

So, your anion will be ${\text{CrO}}_{4}^{2 -}$, a polyatomic ion that consists of one chromium atom, $\text{Cr}$, and four oxygen atoms, $\text{O}$

Assuming that you're familiar with polyatomic ions, you will find that you're dealing with the chromate anion.

When naming on ionic compound, the cation is always named first. This means that your ionic compound will be called

potassium chromate $\to {\text{K"_2"CrO}}_{4}$

Potassium chromate is a yellow solid at room temperature and dissolves in water to form a yellow solution.