Question

Q1. Briefly explain why the Zeff experienced by a valence electron in Cl is larger than in Mg. Q2. Briefly explain why the Zeff difference described in Q1 explains why the radius of Cl is smaller than the radius of Mg. Q3. Briefly explain, in terms of the principal quantum number (n), why the radius of Ba is larger than the radius of Mg.

Answer 1

Answer:

See explanation

Explanation:

Q1:

Chlorine has 17 protons while magnesium has only 12 protons. Recall that the Zeff depends on the size of the nuclear charge. The greater the size of the nuclear charge, the larger the Zeff experienced by a valence electron.

Q2:

The larger the Zeff, the smaller the atomic radius. Since the valence electrons of Cl experience a greater Zeff than those of Mg due to greater size of the nuclear charge, the atomic radius of chlorine will be smaller than that of Mg.

Q3:

The radius of an atom increases as the value of the principal quantum number (n) increases down the group due to addition of more shells. The greater the number of shells added, the greater the principal quantum number (n) and the greater the atomic radius, hence the answer.