Question

Sodium forms ${Na}^{+}$ ion but it doesnot form ${Na}^{2+}$ because of

• A. very low value of first and second I.E
• B. very high value of first and second I.E
• C. high value of first I.E and low value of second I.E
• D. low value of first I.E and high value of second I.E

Answer 1

The correct option is D low value of first I.E and high value of second I.E

$Na$ ($Z=11;1s^2,2s^2{p}^6,3s^1$) readily gives one electron because the resulting ${Na}^{+}$ ($1s^{2}2s^2{p}^6$) has stable configuration. Thus, the first I.E of $Na$ is less. However, removal of an electron from a stable (noble gas) configuration requires high energy and thus, its second I.E is very high.