Question

Which of the following increases in magnitude as the atomic number of alkali metals increases?

• A. Electronegativity
• B. First ionisation potential
• C. Ionic radius
• D. Melting point

Answer 1

Answer: (C)

Ionic radius

Answer 2

(1) Down the group, the atomic size increases with increasing atomic number and so attraction for shared pair of electrons decreases. Hence electronegativity decreases.

(2) Down the group, the atomic size increases with increasing atomic number and so attraction between valence electron and nuclear decreases. Hence ionization energy decreases.

(3) Down the group atomic size increases with increase in number of atomic shells while effective nuclear charge remains constant.

(4) Down the group atomic size increases with increase in number of atomic shells and therefore, the strength of metallic bond decreases. So melting point decreases