The Periodic Table
The Periodic Table — Formulae Sheet (Tabular Form)
| Concept | Formula | Units | Key Notes |
|---|---|---|---|
| Atomic Number | Z = number of protons | — | Determines element identity |
| Mass Number | A = protons + neutrons | — | Total nucleons |
| Number of Neutrons | n = A − Z | — | Subatomic calculation |
| Electronic Configuration | Based on electron shells | — | 2, 8, 8… rule (O Level) |
| Valence Electrons | Group number = outer electrons | — | Determines reactivity |
Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change O Level And IGCSE Chemistry Full Scale Course
| Concept | Formula | Units | Key Notes |
|---|---|---|---|
| Relative Atomic Mass | Aᵣ = (Σ (isotopic mass × abundance)) / 100 | — | Weighted average |
| Isotopes | Same Z, different A | — | Same element |
| Ion Formation | Atoms gain/lose electrons | — | Achieve stable configuration |
| Ionic Charge | Charge = protons − electrons | — | Determines ion type |
Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change O Level And IGCSE Chemistry Full Scale Course
| Concept | Formula | Units | Key Notes |
|---|---|---|---|
| Atomic Radius Trend | Radius ↓ across period | — | More nuclear attraction |
| Atomic Radius Down Group | Radius ↑ down group | — | More shells added |
| Ionisation Energy Trend | IE ↑ across period | — | Stronger nuclear attraction |
| Ionisation Energy Down Group | IE ↓ down group | — | Outer electron further away |
Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change O Level And IGCSE Chemistry Full Scale Course
| Concept | Formula | Units | Key Notes |
|---|---|---|---|
| Reactivity (Metals) | Reactivity ↑ down group | — | Easier electron loss |
| Reactivity (Non-metals) | Reactivity ↓ down group | — | Harder to gain electrons |
| Electronegativity Trend | EN ↑ across period | — | Stronger attraction for e⁻ |
| Shielding Effect | Inner electrons reduce attraction | — | Increases down group |
Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change O Level And IGCSE Chemistry Full Scale Course
| Concept | Formula | Units | Key Notes |
|---|---|---|---|
| Group 1 Trend | Reactivity ↑ down group | — | More reactive metals |
| Group 7 Trend | Reactivity ↓ down group | — | Less reactive halogens |
| Transition Metals | Variable oxidation states | — | Form coloured compounds |
| Noble Gases | Full outer shell | — | Very unreactive |
Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change O Level And IGCSE Chemistry Full Scale Course