Question

First ionisation enthalpy values of the first four group 15 elements are given below. Choose the correct value for the element that is a main component of the apatite family:

• A. 1012 , \(\text{kJ mol}^{-1}\)
• B. 1402 , \( \text{kJ mol}^{-1}\)
• C. 834 , \( \text{kJ mol}^{-1}\)
• D. 947 , \( \text{kJ mol}^{-1}\)

Hint:

The ionization enthalpy increases across a period as the effective nuclear charge increases, but it decreases down a group due to an increase in atomic size. Phosphorus is a key element in the apatite family and has a relatively moderate ionization enthalpy.

Answer 1

The Correct Option is A

The apatite mineral group primarily consists of phosphate ions, with phosphorus being a key component. Phosphorus, located in Group 15, has an ionization enthalpy of \( 1012 \, \text{kJ mol}^{-1} \). Therefore, the ionization enthalpy of phosphorus is the correct value.
Consequently, the correct option is \( \boxed{(1)} \).