Question

What is the relationship between atomic radius and electronegativity?

Answer 1

Atomic radius tells us the size of any atom, as it is the distance from the center to the electron cloud. While, electronegativity is the ability of any atom to attract electrons. Atomic radius can be measured and has units, while electronegativity has no units.

Complete answer:
In the periodic table, as we move from left to right in a period, we can see the trend that atomic number increases, while the radius of elements decreases, as the size of the atoms decreases. On the other hand, the electronegativity of the elements increases.
The atomic radius of any element is the measure of one half of the distance between the nucleus and the electron cloud, or the valence electron. Electronegativity is defined as the property of any element to attract the shared pair of electrons towards itself by creating partial negative charge on the electronegative atom, and positive charge on the electropositive atom.
As the size of any atom or the atomic radius decreases, we can see that electronegativity increases. This is due to the fact that the number of electrons increases, with more number of electrons there is more electron density that creates more polarization that helps the atom attract electrons towards itself and create partial charges.
Hence, atomic radius and electronegativity are related in the context that, with decrease in radius electronegativity increases due to more electron density.

Note:
The most electronegative elements in the periodic table have the lowest size. These elements are fluorine, being the most electronegative, followed by oxygen. The measure of electronegativity is done on scales like Pauling scale, that has given fluorine an electronegativity of 4.