From which of these atoms in the ground state can a valence electron beremoved using the least amount of energy? (1) nitrogen (3) oxygen (2) carbon (4) chlorine

Carbon can-be valence electron that could-be removed using the least amount of energy.

Correct Answer: option (4) chlorine

Reason:

Energy required to remove electron from electron from ground state is referred as ionization energy. Ionization energy depends on electronegativity of species. Greater the electronetivity, more will be the energy required to remove electron from valance shell. Among the listed element, chlorine has maximum electronegativity. Hence, it will have maximum ionization energy. The first ionization energy of Cl is 1251.19 kJ mol ‑1.