Let's determine the correct formula for the chromate ion.
1. Identify the constituent atoms:
- The chromate ion consists of four oxygen atoms and one chromium atom.
2. Determine the charge:
- A chromate ion has two extra electrons. Extra electrons mean that the ion carries a negative charge.
3. Express the ion's formula:
- Since we have four oxygen atoms, we write this as [tex]\( \text{O}_4 \)[/tex].
- We have one chromium atom, so we write this as [tex]\( \text{Cr} \)[/tex].
- The overall ion has a 2- charge, which means it carries a charge of [tex]\( 2- \)[/tex].
4. Combine the components:
- Join the chromium atom (Cr) with the four oxygen atoms (O[tex]\(_4\)[/tex]), and indicate the 2- charge.
The correct formula for the chromate ion is:
[tex]\[ \text{CrO}_4^{2-} \][/tex]
This matches the third option:
[tex]\[ CrO_4^{2-} \][/tex]
