STANDARDChemistry-Chemical Bonding and Molecular Structure

STANDARD Chemistry Electron Affinity MCQ Question

Type: MCQ-conceptual-Medium-Class 11

The formation of the oxide ion O₂⁻(g) requires first an exothermic and then an endothermic step as shown below O(g) + e⁻ = O⁻(g) ΔH° = -142 kJ mol⁻¹ O⁻(g) + e⁻ = O₂⁻(g) ΔH° = 844 kJ mol⁻¹ This is because

A

O⁻ ion will tend to resist the addition of another electron

B

Oxygen has high electron affinity

C

Oxygen is more electronegative

D

O⁻ ion has comparatively larger size than oxygen atom

Correct Answer

Option A

Detailed Explanation

The addition of a second electron to an atom or ion is always endothermic due to electron-electron repulsion.

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