Mg2+ ?

-magnesium ion
-sodium ion
-manganese ion
-calcium ion

Magnesium ion.

Explanation:

Before charge= 2.8.2

after charge= (2.8)2+

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons