Question

Which set of elements shows positive electron gain enthalpy?
(1) He, N, O
(2) Ne, N, CI
(3) O, CIF
(4) N, He, Ne

Answer 1

Hint: The sum of energy emitted when an electron is applied to an isolated gaseous atom is known as electron gain enthalpy. Energy may be emitted or absorbed during the insertion of an electron. As a result, the nuclear force exerted on electrons in the case of Sodium would be less.

Complete answer:
Electron gain enthalpy is the amount of the energy released when an electron is added to an isolated gaseous atom. During the injection of an electron, energy may be released or consumed. As a consequence, in the case of Sodium, the nuclear force exerted on electrons will be less. Electron gain enthalpy is the amount of the energy released when an electron is added to an isolated gaseous atom. During the injection of an electron, energy may be released or consumed. As a consequence, in the case of Sodium, the nuclear force exerted on electrons will be less.
The patterns in electron gain enthalpy values within a time are irregular for elements in groups 2, 15, and 18, because their atoms have symmetrical configurations (filled and half-filled orbitals in the same subshell) and therefore have little need to pick up extra electrons because their arrangement would become unsymmetrical or less stable.
Elements with fully filled orbitals do not accept electrons, making them impossible. As a result, when adding some heat energy, they are more likely to accept the electron. This indicates that the element has a positive gain enthalpy. He and Ne are noble gases that would not readily accommodate an electron.
Hence option A is correct.

Note:
The change in energy (in kJ/mol) of a neutral atom (in the gaseous phase) when an electron is inserted to form a negative ion is known as electron affinity. In other words, the probability of a neutral atom receiving an electron.