Question

Identify the incorrect statement(s).

• A. Fluorine is the most electronegative element and has the highest electron affinity
• B. The order of electron affinity for group 16 is $S>O>Se>Te>Po$
• C. Non metallic character and electronegativity follow the same trend across a period
• D. Magnitude of electron gain enthalpy and ionization energy follow opposite trends on moving down the group.

Answer 1

Answer: (A), (B), (D)

Magnitude of electron gain enthalpy and ionization energy follow opposite trends on moving down the group.

The electron affinity can be defined as the amount of energy released when an electron is attached to a neutral atom or molecule in the gaseous state to form a negative ion. Fluorine is the most electro negative element, but chlorine has highest electron affinity because due to the small volume of fluorine it has high charge density.

The electron affinity generally decreases down the group. Atomic size increases down the group.But electron affinity of oxygen is least because it has relatively high electron density due to inter electronic repulsion. So the actual order is $S>Se>Te>Po>O$

Non metallic character and electronegativity both increases as we move from left to right.

As we go down the group, size increases and $Z_{eff}$ decreases. So, the electron-nuclei attractions also decrease resulting in the decrease in magnitude of both electron gain enthalpy and ionization energy.