Question

Consider the following statements:

(I) The radius of an anion is larger than that of the parent atom.
(II) The ionization enthalpy generally increases with increasing atomic number in a period.
(III) The electronegativity of an element is the tendency of an isolated atom to attract an electron.

Which of the above statements is/are 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

Let us go through each statement.

(I) The radius of an anion is larger than that of the parent atom.
This is definitely true. When an electron(s) is added and the nuclear charge remains the same, the repulsion between the electrons exceeds that of the attraction of the nucleus. So the size increases as compared to the original atom.

(II) The ionization enthalpy generally increases with increasing atomic number in a period.
As we go across the period, ionization enthalpy increases due to an increase in effective nuclear charge.

(III) The electronegativity of an element is the tendency of an isolated atom to attract an electron.
Always remember that electronegativity is the tendency of an atom to attract a bonding pair of electrons. Electronegativity is not defined for isolated atoms. That would be electron affinity.

So, (III) is wrong.