What is the oxidation state of an individual carbon atom in caco3?

The oxidation state of the carbon is + 4.

Explanation:

Calcium is in group 2 of the periodic table, therefore, its oxidation state is + 2.

The oxidation state of the oxygen is - 2.

As the compound is neutral, the sum of the oxidation states of all atoms must be 0.

Oxidation State Ca + Oxidation State C + (Oxidation State O) * 3 = 0

+2 + x + (-2) * 3 = 0

2 + x - 6 = 0

x = 6 - 2

x = 4

Hence, the oxidation state of the carbon is + 4.