Final answer:
The formula for strontium nitrite is Sr(NO2)2, which is written by balancing the charges of the strontium cation and the nitrite anion to ensure the compound is electrically neutral.
Step-by-step explanation:
The formula for strontium nitrite is Sr(NO2)2. In this chemical formula, Sr represents a strontium cation with a charge of +2, and NO2 represents a nitrite anion with a charge of -1. Since an ionic compound must be electrically neutral, two nitrite ions are needed to balance the +2 charge of the strontium cation, leading to the formula Sr(NO2)2. This formula indicates that there are two nitrite anions for every strontium cation in the compound.