Question

The first ionization enthalpies of the elements X, Y, Z of the second period are 899, 1402, 520 kJ/mol respectively. X, Y, Z respectively are:

• A. Li, B, N
• B. Be, N, Li
• C. Be, Li, N
• D. Li, N, Be

Hint:

Ionization enthalpy generally increases across a period and decreases down a group in the periodic table.

Answer 1

The Correct Option is B

Step 1:
Ionization enthalpy increases as we move across a period (from left to right) and decreases as we move down a group in the periodic table.

Step 2:
From the given values:
- 899 kJ/mol corresponds to the element with the highest ionization enthalpy, which is Be.
- 1402 kJ/mol corresponds to the element with the second-highest ionization enthalpy, which is N.
- 520 kJ/mol corresponds to the element with the lowest ionization enthalpy, which is Li.
Thus, the correct order is Be, N, Li.