Question

Explain, why electronegativity of Li is greater than Mg?

Answer 1

We need to apply some basic concepts of inorganic chemistry. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. Smaller the atom, higher is its electronegativity.

Complete step by step answer
From the above question we can say that electronegativity of an element is its tendency to attract bond pair electrons.
So, first we need to write down the electronic configuration of both elements. The electronegativity of Li and Mg can be understood by their electronic configuration as follows
$Li:1{s^2}2{s^{}}$
$Mg:1{s^2}2{s^2}2{p^6}3{s^2}$
Li has 1 electron in its valence shell (n=2). However, Mg has 2 electrons in its valence shell (n=3). The valence shell of Li is closer than that of Mg which makes Li more electronegative than Mg.

Note:
Electronegativity is a function of an atom's ability to attract an electron binding pair. The most frequently used is the Pauling scale. Fluorine is assigned a value of $4.0$ , and values that are the least electronegative at $0.7$ range down to caesium and francium. Electronegativity decreases in classes from bottom to top and increases over time from left to right. The most electronegative element is, therefore, fluorine, while francium is one of the least electronegative elements. The degree to which an atom attracts electrons in a chemical bond is described by electronegativity. If the difference in electronegativity is greater than $1.7$ , the character of the bond will be ionic. If the difference in electronegativity is between $0.4$ and $1.7$ , the character of the bond is polar covalent. Electronegativity is an example of an atom's ability to attract electrons. It is proportional to the difference between the potential for ionization of an atom and its attraction to the electron.