What is the chemical formula for nickel(II) carbonate?

Nickel(II) carbonate is a compound that consists of nickel ions with a +2 oxidation state and carbonate ions. The name "nickel(II)" indicates that nickel has a +2 charge. The carbonate ion has the formula CO3 and carries a -2 charge.

To balance the charges between nickel and carbonate, one nickel ion (Ni²⁺) will combine with one carbonate ion (CO3²⁻). Therefore, the formula for the compound is NiCO3.

This balance is crucial because in chemical formulas, the overall charge must be neutral. In this case, the +2 charge from one nickel ion is completely offset by the -2 charge from one carbonate ion, resulting in a neutral compound.

Other choices do not correctly represent nickel(II) carbonate. For example, NiCO represents a different composition that does not exist as nickel(II) carbonate and lacks the required carbonate ion. NiC2O4 indicates a different ratio and implies a different compound, possibly nickel(II) oxalate. Ni2CO3 suggests that two nickel ions would combine with one carbonate ion, which does not achieve the necessary charge balance.

Thus, the correct chemical formula for nickel(II) carbonate is