Answer:
The answer to your question is below
Step-by-step explanation:
1.- Barium and magnesium are in different periods, Barium is in period 6 and magnesium is in period 3. This means that Barium has 3 more levels of energy than magnesium. Both metals have the same valence number but the electronic configuration of Magnesium is [Ne] 3s2 and from Barium is [Xe]6s2.
2.- Yes, that is correct. Sodium loses 1 electron when it ionizes. Then its ion is Na+1.
Atoms become stable when they acquire 8 electrons in their outermost shell, so, sodium acquires 8 electrons when it loses electrons.
3.- Neutral Sodium is bigger than its ion because it has one more shell.