Question

The most electronegative element belongs to:

Answer 1

Hint: Electronegativity increases as we move across the period and decreases as we move down the group. Group 1 contains elements with least electronegativity and group 17 contains elements with most electronegativity.

Complete step by step solution:
Atoms attract a shared pair of electrons in a bond towards itself and this capacity or ability of an atom to do so is known as electronegativity. It decreases down the group and increases across the period. Electronic configuration of atoms gives rise to this property.
 Most of the atoms follow octet rule (eight electrons in its valence shell). Since elements of group 17 have 7 electrons in their valence shell, it requires less energy in accepting electrons rather than giving 7 electrons. As we move across a period nuclear charge increases whereas atomic size decreases, therefore, electronegativity increases across a period.
In a group as we move down the group nuclear charge increases but it is counteracted by the increase in a shell, therefore, electronegativity decreases down the group. Therefore, elements of group 17 contain most electronegative elements in which fluorine is most electronegative.

Note: Electronegativity is a tendency of atoms therefore, it is a dimensionless property. Group 17 is the most electronegative group in periodic table and group 1 is least electronegative group. Electronegativity arises because elements want to follow octet rule and since nuclear charge nuclear charge increases as we across a period and overall electronegativity decreases down the group due to increase in size of elements which counteract the increase in nuclear charge.