Question

what is the correct formula for the compound formed by ca²⁺ and no₂⁻?
a. ca₂no₂
b. ca(no₂)₂
c. ca₂(no)₂
d. cano₂

Explanation:

Step1: Determine ion charges

Calcium ion ($Ca^{2 + }$) has a charge of +2, and nitrite ion ($NO_{2}^{-}$) has a charge of - 1.

Step2: Balance charges

To form a neutral compound, the total positive charge must equal the total negative charge. Since the calcium ion has a +2 charge and the nitrite ion has a -1 charge, we need 2 nitrite ions to balance the +2 charge of one calcium ion.

Answer:

B. $Ca(NO_{2})_{2}$