Answer:
2. Na, Mg, N, O, F (Option 2)
Explanation:
Let's look the electronegativity in the periodic table for each element.
F → 4
Na → 0.9
Mg → 1.2
O → 3.4
N → 3
So the correct orden is Na, Mg, N, O, F
Electronegativity is the ability for the atoms to catch electrons in a bond.
It is a periodic table which increase in a diagonal way, from Fr and Ra, the less electronegatives to F, the most.