Question

Consider the following statements

I. The radius of an anion is larger than that of the parent atom.

II. The ionization energy generally increases with the increasing atomic number in a period.

III. The electronegativity of elements increases on moving down across a group.

Which of the above statements is correct?

• A. I alone
• B. II alone
• C. I and II
• D. II and III

Answer 1

The correct option is C

I and II

Explanation of the correct option:

(A) The size of an anion is always larger than its parent atom because the anions have more electrons than the parent atom which results in increased repulsion among the electrons and a decrease in the effective nuclear charge per electron.

(B) The ionization energy generally increases with the increasing atomic number in a period because across a period from left to right, because an increase in nuclear charge attracts the electrons strongly towards itself and therefore more energy is required to remove electrons.

Explanation of the incorrect option:

• Electronegativity: It is the tendency of an atom in a molecule to attract the shared pair of electrons towards itself.
• As we move down the group atomic size increases due to this the ability of nucleus to attract electrons decreases. So, electronegativity decreases down the group.

Conclusion: Hence, option (C) i.e. (I) and (II) is correct and The radius of an anion is larger than that of the parent atom ,and The ionization energy generally increases with the increasing atomic number in a period.