Answer:
No, it will not exist in real life
Step-by-step explanation:
Let us consider the electronic configuration of magnesium; Ne 3s2
We must also assume that the compound Mg20 is ionic. If this is the case, then it involve Mg+ and O^2-.
The electronic configuration of Mg+ is Ne 3s1. We can see that this specie has not yet attained a stable noble gas configuration, As a result of this, the ion is not stable. Hence, Mg20 does not occur in real life,