Which has higher electron affinity: Cl or Na⁺?

Answer: Na⁺ has a higher electron affinity than Cl.

The energy released when an electron is added to a neutral gaseous atom is known as electron affinity.

• The electron affinity increases across a period while it decreases down a group.
• In halogens chlorine posses the highest electron affinity in the periodic table.
• As atomic radii increases, electron affinity increases.
• As nuclear charge increases, electron affinity increases.
• It decreases down a group and increases across a period.
• The unit for electron affinity is kilo joules per mole.