The ionic compound CaO crystallizes with the same structure as sodium chloride.

In this structure, how many $O^{2-}$ are in contact with each $C{a}^{2+}$ ion $($Hint: Remember the

pattern of ions shown in the figure repeats over and over again in all three directions.$)$

Express your answer as an integer.

Part B

Would energy be consumed or released if a crystal of CaO was converted to a collection of

widely separated $Ca-O$ ion pairs?

neither

consumed

consumed and released equally

released

Part C