`IE_(1)` of Na is less than that of `Mg-explain.

Explanation

Sodium atom has only one electron in its outer orbit and by losing that electron it gets stability by acquiring octect. Further in the nucleus of sodium there are number of protons than in magnesium. So nuclear attraction on the electrons in sodium is less than `IE_(1)` of Mg .
In Na the outer orbit has stable octet. To remove the electron from stable octect more energy is required . But in `Mg^(2)` there is one more electron out side the stable octet i.e.,in 3s orbital. To remove the 3s electron the energy required is less .So `IE^(2)` of Na is greater than `IE^(2)` of Mg.