NEETChemistryStructure of Atom
Assertion (A): First ionisation enthalpy of oxygen is less than that of nitrogen Reason (R): Atoms with half-filled or completely filled orbitals are less stable The correct option among the following is
Options
- A(A) and (R) are true. (R) is the correct explanation of (A)
- B(A) and (R) are true, but (R) is not correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
C. (A) is true but (R) is false
Step-by-step solution
The first ionisation enthalpy of oxygen is less than that of nitrogen. This is due to the stability of halffilled electronic configuration. Nitrogen has half filled electronic configuration and hence its ionisation energy is greater than oxygen. In oxygen, after losing its electron, it goes to half filled electronic configuration and hence, it has less ionisation energy than litrogen.