Here's how to determine the number of valence electrons in the carbonate ion (CO₃²⁻):

1. Valence Electrons of Individual Atoms:

* Carbon (C): Group 14, 4 valence electrons

* Oxygen (O): Group 16, 6 valence electrons

2. Total Valence Electrons (Ignoring Charge):

* Carbon: 1 atom * 4 electrons = 4 electrons

* Oxygen: 3 atoms * 6 electrons = 18 electrons

* Total: 4 + 18 = 22 electrons

3. Account for the Charge:

* The 2- charge indicates that the ion has gained two extra electrons.

* Add 2 to the total: 22 + 2 = 24 electrons

Therefore, the carbonate ion (CO₃²⁻) has 24 valence electrons.