Question

Explain, why electronegativity of Li is greater than Mg?

Answer 1

Electronegativity of an element is its tendency to attract bond pair electrons.

The electronegativity of Li and Mg can be understand by their electronic configuration as follows-

$Li:1s^{2}2s^1$

$Mg:1s^{2}2s^{2}2p^{6}3s^2$

Li has 1 electron in its valence shell (n=2). However, Mg has 2 electrons in its valence shell (n=3). The valance shell of Li is closer than that of Mg which makes Li more electronegative than Mg.