Question

The Ionization energy and electron affinity of an element are 17.42eV and 3.42eV respectively, find the E.N. of the element on Pauling scale:
A.10.435
B.3.726
C.0.166
D.2.88

Answer 1

To solve this question, we need to first calculate the electronegativity on mulliken scale. After finding this value we will get the Pauling scale value by dividing the Milliken scale value by 2.8.

Formula used:
E.N. on Pauling scale $= \dfrac{{E.N.\,on\,mulliken\,scale}}{{2.8}}$

Complete step by step answer:
Basically, the ionization energy of an element is a measure of the difficulty in removing an electron from an atom or ion or it is the tendency of an atom or ion to surrender an electron. We can also say that it is the measure of strength by which an electron is held in a place. Moreover, electron affinity is the amount of energy released when an electron is added to a neutral atom to form an anion.
Now, the mulliken scale is used to calculate the electronegativity of an element. It simply considers the electronegativity of an element as the average of the ionization potential and the electron affinity of that element. But the Pauling scale is more popular than Mulliken scale and it is often required to convert the values from Mulliken scale to Pauling scale.
Now, we will first find the electronegativity on mulliken scale,
$= \dfrac{{I.E. + E.A.}}{2}$
$= \dfrac{{17.42 + 3.42}}{2}$
= 10.42
Now, E.N. on Pauling scale will be,
$= \dfrac{{E.N.\,on\,mulliken\,scale}}{{2.8}}$
$= \dfrac{{10.42}}{2}$
= 3.72
Hence, option B is correct.

Note: Mulliken proposed that the arithmetic mean of the first ionization energy and the electron affinity should be a measure of tendency of an atom to attract electrons. Moreover, Pauling scale is based on the bond enthalpies.