Magnesium reacts with an element (X) to form an
ionic compound. If the ground state electronic
configuration of (X) is ``1s^2`` ``2s^2`` ``2p^3``, the simplest
formula for this compound is
(1) ``\ce{Mg2X3}`` (2) ``\ce{MgX2}``
(3)``\ce{Mg2X}`` (4)``\ce{Mg3X2}``