Here's why:

* Ca: Represents the element Calcium.

* Cr: Represents the element Chromium.

* O₄: Represents four Oxygen atoms.

Since Chromium is in the +6 oxidation state in this compound, it forms the chromate ion (CrO₄²⁻). Calcium has a +2 charge, so it combines with the chromate ion in a 1:1 ratio to form a neutral compound.