Question

If A, B, C, D are four different elements with outer electronic configurations as:

A = 4s² 4p⁴, B = 4s² 4p⁵, C = 5s² 5p⁴, D = 5s² 5p⁵

Find the element having the highest ionization enthalpy (Δ₁H₁).

Options

• A

• B

• C

• D

Answer 1

B

Explanation:

Ionisation enthalpy decreases down the group and increases from left to right in the modern periodic table.

B > A > D > C