Final answer:
The correct formula for the ionic compound between Group 2 element A and Group 16 element B is AB since the charges of a 2+ cation and a 2- anion balance each other to form a neutral compound.
Step-by-step explanation:
The correct formula for an ionic compound formed between a Group 2 element, A, and a Group 16 element, B would take into account the charges of the ions each element forms. Group 2 elements form 2+ cations and Group 16 elements form 2- anions. The charges must balance for the compound to be neutral. Therefore, one ion of element A would balance with one ion of element B, making the correct formula AB. So, the correct answer is A. AB.