Textbook Problem

Atoms form ions so as to achieve electron configurations similar to those of the noble gases. For the following pairs of noble gas configurations, give the formulas of two simple ionic compounds that would have comparable electron configurations.

msp;  $\begin{array}{l}\text{a}.\left[\text{He}\right]\text{ and }\left[\text{Ne}\right] \text{c}.\left[\text{He}\right]\text{ and }\left[\text{Ar}\right]\\ \text{b}.\left[\text{Ne}\right]\text{ and }\left[\text{Ne}\right] \text{d}.\left[\text{Ne}\right]\text{ and }\left[\text{Ar}\right]\end{array}$