Which among the following has lowest electron affinity?

The correct answer is Argon.

Key Points

• Argon has all filled orbitals as well as a filled valence shell.
• As a result, it doesn’t want to lose or gain any electrons.
• Hence, argon has the lowest electron affinity.

Important Points

• Electron affinity is the change in energy of a neutral atom (gaseous phase) when an electron is added to the atom to form a negative ion.
  • Electron affinity increases from left to right in the Periodic Table.
  • Electron affinity decreases down the groups.
• The electronic affinity of the Noble gases, Alkali metals, and Alkali earth metals are close to zero.

Additional Information

Fluorine

• Atomic number: 9.
• Symbol: F.
• Most electronegative element.
• First isolated by Henri Moissan.

Bromine

• Atomic number: 35.
• Symbol: Br.
• It is the third-lightest halogen and is a fuming red-brown liquid at room temperature that evaporates readily to form a similarly coloured gas.
• Its properties are thus intermediate between those of chlorine and iodine.

• Atomic number 17.
• Symbol Cl.
• Discovered by Carl Wilhelm Scheele.
• Second-lightest of the halogens.