Explain the trend in general of (i) electron affinity (ii) electronegativity of elements:
(a) on moving from left to right across a period
(b) on moving down a group.
Give reasons for the change in each periodic trend.

Trends in (i) Electron Affinity and (ii) Electronegativity:

(a) Across a Period (Left to Right):

• Electron Affinity: Increases. Decreasing atomic size and increasing nuclear charge make atoms more able to attract electrons.
• Electronegativity: Increases. Smaller atoms with higher nuclear charge pull shared electrons more strongly.

(b) Down a Group:

• Electron Affinity: Decreases. Although nuclear charge increases, the larger atomic size weakens the attraction for additional electrons.
• Electronegativity: Decreases. Larger atomic size reduces the atom’s ability to attract shared electrons despite the increased nuclear charge.