What is the correct formula for zinc nitrite?

The correct formula for zinc nitrite is Zn(NO2)2. To understand this, we must consider the charges of the ions involved in this compound.

Zinc typically has a charge of +2, as it forms the Zn²⁺ ion. Nitrite is a polyatomic ion with the formula NO2 and a charge of -1. To achieve electrical neutrality in the compound, the positive charge of zinc must balance the negative charges from the nitrite ions.

Since one Zn²⁺ ion has a charge of +2, it requires two NO2⁻ ions (each with a -1 charge) to balance it out. Thus, you combine one zinc ion with two nitrite ions, leading to the formula Zn(NO2)2.

The other selections either do not adhere to the correct stoichiometry or misrepresent the charges needed to form a neutral compound. It's important to carefully assess the charges of ions when determining the correct formula for ionic compounds, and this understanding directly leads to identifying that Zn(NO2)2 is indeed the proper formula for zinc nitrite.