Question: why is mgcl2 formed instead of mgcl?
Answer: 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.