Question

Which of the following is the least electronegative?
(A) Hydrogen
(B) Lithium
(C) Nitrogen
(D) Sulphur
(E) Phosphorous

Answer 1

Electronegativity is the characteristic of an atom by which it pulls an electron to itself in a bonded situation. On moving in the periodic table, the electronegativity increases acres the period and decreases down the group.
Step by step explanation:
The periodic table classifies the elements in such a manner that they are placed according to increasing atomic number. The elements on the right of the periodic table have more electrons in their valence shell than those in the left.
The left of the periodic table houses the alkali metal. The alkali metals generally are one electron excess of the nearest noble gas configuration. On losing an electron it gains stability. The halogens are one electron short of the nearest noble gas configuration and hence it accepts an electron to form the nearest noble gas configuration. The acceptance of electrons forms the anion and the giving up of electrons forms cation.
Thus, when a bond is being formed then the positive charge is formed on the metal and the electrons are attracted by the non metals. Hence the non metals are electronegative and the alkali metals are electropositive.
Hence the correct option is lithium
Additional information:
The most electropositive element is francium as it is present on the bottom of the group 1 element.
Although hydrogen starts the periodic table it has an electronegativity comparable to carbon.
The most electronegative element is fluorine.
Note:
Electronegativity and electron gain enthalpy are very confusing terms. Electron affinity is the amount of energy released by an isolated gaseous atom when an electron is added to it. Electronegativity is the property of the bonded atom. Fluorine is the most electronegative atom and chlorine has the greatest electron gain enthalpy.