Question

Which of the following has the highest electronegativity?
(A) \[H\]
(B) \[Na\]
(C) \[Ca\]
(D) \[F\]

Answer 1

Hint: Electronegativity is the tendency to pull or attract the shared pairs of electrons in a covalent bond towards itself. Electronegativity is a property mainly observed in non-metallic elements of the modern periodic table that usually lie towards the extreme right side.

Complete Step By Step Answer:
Electronegativity depends on the effective nuclear charge and therefore decreases on descending a group and increases on going left to right in a period. The elements in the extreme right corner of the periodic table possess high electronegativity values due to their small size and high nuclear charges.
Hydrogen being the first member of the periodic table contains a single electron and does not have a high nuclear charge due to the presence of a single proton in its nucleus.
Sodium and calcium are alkali and alkaline earth metals belonging to the first and the second group of periodic table respectively. These two elements have large atomic radii, low ionization enthalpies and low nuclear charges due to which they are mainly electropositive in nature and have a tendency to lose electrons rather than attracting electrons towards them.
Fluorine has an exceptionally small size and sufficient nuclear charge that makes it the most electronegative atom of the periodic table. Fluorine is so electronegative that it even forms bonds with xenon which is an inert gas. It is the first member of the seventeenth group, therefore it is towards the extreme right of the period and topmost in the group.
\[ \Rightarrow \] Hence, Fluorine is the element with highest electronegativity and option (d) is correct.

Note:
The Pauling scale value of electronegativity for fluorine is \[3.98\] and no other element is assigned a value higher than the fluorine atom. It is due to the high electronegativity that fluorine stabilizes the higher oxidation states of central atoms in many compounds.