Question

Instead of writing compound as MgCl₂ why can't we write us MgCl​

Answer 1

To make MgCl, you would need to remove 1 electron from the magnesium to produce Mg+ ions. That just needs the first ionisation energy of the magnesium. ... The net effect is that the enthalpy change of formation of MgCl2 is more negative than that of MgCl, meaning that MgCl2 is the more stable compound of the two.

Answer 2

Answer:

Because in the compound magnesium chloride or MgCl₂ , two atoms of Chlorine combines with one atom Magnesium hence forming the compound MgCl₂.

That's why we can't write it as MgCl.

Hope it helps!