Question

Cation and anion of Cr(CO3)3

Answer 1

Answer: Cation: $Cr^{6+}$

Anion: $CO_3^{2-}$

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.  

Here Chromium is having an oxidation state of +6 called as $Cr^{6+}$ cation and carbonate $CO_3^{2-}$ is a polyatomic anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $Cr(CO_3)_3$.

The cations and anions being oppositely charged attract each other through strong coloumbic forces and form an ionic bond.

Answer 2

Chromium has a positive charge (it's a multivalent metal with multiple positive charges)

Carbonate has a negative charge (-2)

Chromium would be the cation, and carbonate would be the anion.