Deep-Dive Guides · Main Group — p-Block
p-Block Elements — the complete descriptive deep dive
The p-block spans the whole spectrum of chemistry — metals, metalloids and non-metals — inside six groups, so it is the single largest reservoir of descriptive-inorganic exam marks.
Free extract — the opening section of the guide, in full.
0. How to use this guide — the p-block logic map
The p-block looks like a hundred disconnected facts. It is really four reusable ideas applied group by group. Fix these first and the descriptive chemistry becomes derivable.
| Master idea | What it predicts | Where it bites hardest |
|---|---|---|
| First-member anomaly (period-2 element differs) | Small size, no d-orbitals, strong pπ–pπ multiple bonding, max covalency 4 | N vs P, O vs S, F vs Cl, C vs Si, B vs Al |
| Inert-pair effect (ns² reluctant to ionise low down) | Heavier members favour oxidation state (group − 2); lower state becomes oxidising when high | Tl(I)>Tl(III), Pb(II)>Pb(IV), Bi(III)>Bi(V) |
| Metal ↔ non-metal gradient | Non-metal (top-right) → metalloid (staircase) → metal (bottom-left); oxides go acidic → amphoteric → basic | C non-metal … Pb metal; N acidic oxides … Bi basic |
| d-orbital availability & expanded octet | Period-3+ elements can exceed an octet (SF₆, PCl₅, XeF₄); period-2 cannot (no NF₅, no OF₆) | PCl₅ exists, NCl₅ does not; SF₆ exists, OF₆ does not |
Read the rest of this guide
The remaining 12 sections — Cross-cutting trends & anomalies, Group 13 — the boron family (B, Al, Ga, In, Tl), Group 14 — the carbon family (C, Si, Ge, Sn, Pb), Group 15 — the nitrogen family / pnictogens (N, P, As, Sb, Bi) and more — are part of ChemVidya Full Access, along with the other guides, the books, the study notes and 6,000+ practice questions with worked solutions.