Key Points
Key Points: Group 13 Elements - The Boron Family
General electronic configuration: ns² np¹.
| Element | Symbol | Electronic Configuration |
|---|---|---|
| Boron | B | [He] 2s² 2p¹ |
| Aluminium | Al | [Ne] 3s² 3p¹ |
| Gallium | Ga | [Ar] 3d¹⁰ 4s² 4p¹ |
| Indium | In | [Kr] 4d¹⁰ 5s² 5p¹ |
| Thallium | Tl | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹ |
- All group 13 elements predominantly show a +3 oxidation state.
- Aluminium is the third most abundant element in Earth's crust (after oxygen and silicon).
- Boron is non-metallic; it does not react with non-oxidising acids but dissolves in strong oxidising acids like HNO₃ (conc.) and H₂SO₄ (conc.).
Key Points: Group 14 Elements - The Carbon Family
General electronic configuration: ns² np²
| Element | Symbol | Configuration |
|---|---|---|
| Carbon | C | [He] 2s² 2p² |
| Silicon | Si | [Ne] 3s² 3p² |
| Germanium | Ge | [Ar] 3d¹⁰ 4s² 4p² |
| Tin | Sn | [Kr] 4d¹⁰ 5s² 5p² |
| Lead | Pb | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p² |
- Size & Energy Trends: Down the group, atomic and ionic radii increase, while ionisation energy decreases.
- Oxidation States: Show +4 and +2 states → +4 stable at top (C, Si), +2 becomes stable down the group (Sn, Pb) due to inert pair effect.
- Metallic Character: Increases down the group → C is non-metal, Si/Ge metalloids, Sn/Pb metals.
- Covalent Nature: Tendency to form covalent compounds decreases down the group as metallic character increases.
- Anomalous Behaviour of Carbon: Due to small size, high electronegativity, absence of d-orbitals, and high catenation.
- Catenation & Bonding: Carbon shows maximum catenation and strong covalent bonding, forming chains and rings.
Allotropes of Carbon:
- Crystalline: Diamond (hardest), Graphite (conducts electricity), Fullerene (spherical)
- Amorphous: Coke, Charcoal (adsorbent), Lampblack (~98–99% carbon)
