Here's why:

* K₂CrO₄ is the chemical formula for potassium chromate.

* Potassium (K) is a Group 1 element, so it always forms a +1 ion (K⁺).

* Chromate (CrO₄²⁻) is a polyatomic ion with a -2 charge.

To balance the charges in the compound, you need two potassium ions (2 x +1 = +2) to counter the -2 charge of the chromate ion.