For the hypothetical compound ax2, which of the following statements is true? . a.) a is a nonmetal from group 3a, and x is a metal from group 1a.. b.) a is a metal from group 1a, and x is a metal from group 7a.. c.) a is a metal from group 3a, and x is a nonmetal from group 5a.. d.) a is a metal from group 2a, and x is a nonmetal from group 7a..

The cations has positive charges that are metals while the anions have negative charges that are non-metals. Upon reaction, there is an exchange in charges that are reflected in the subscripts of the atoms. In this case, compound AX2 must have a cation, A belonging to group 2 A with +2 charge and anion, X  belonging to Group 7A with -1 charge. Answer is D.