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.