Question

'Generally, electron affinity values of elements decrease from top to bottom in a group of non-metallic elements. However, elements of 2nd period have lower electron affinity values than do the corresponding elements of 3rd period: Comment on this statement.

Answer 1

• The amount of energy released when an electron is added to an isolated neutral gaseous atom in its lowest-energy state to produce an anion is called its electron affinity.
• The electron affinity values of the 3rd-period element are greater than that of the 2nd-period element.
• This is due to an exceptional increase in atomic radius on moving top to bottom in a group.
• Hence, a higher amount of energy is released on the addition of electrons in the 3rd period.