Question

Which of the following characteristics regarding 7 halogens is not correct?

• A. Ionization energy decreases with increase in atomic number.
• B. Electronegativity decreases with increase in atomic number.
• C. Electron affinity decreases with increase in atomic number.
• D. Enthalpy of fusion increases with increase in atomic number

Answer 1

Answer: (C)

Electron affinity decreases with increase in atomic number.

• Electron Affinity (decreases down the group) Since the atomic size increases down the group, electron affinity generally decreases (At < I < Br < F < Cl). An electron will not be as attracted to the nucleus, resulting in a low electron affinity.
  
• However, fluorine has a lower electron affinity than chlorine. Chlorine has higher electron gain enthalpy than fluorine because due to the small size of fluorine some energy is utilized in overcoming the force of repulsion among electrons.
  
• Hence option C is an incorrect answer.