Bonding and Structure
Bonding and Structure — Formulae Sheet (Tabular Form)
| Concept | Formula | Units | Key Notes |
|---|---|---|---|
| Ionic Charge Balance | Total positive charge = total negative charge | — | Compound must be neutral |
| Number of Bonds (Covalent) | Bonds = 8 − valence electrons (for non-metals) | — | Based on octet rule |
| Number of Bonds (Hydrogen) | Bonds = 2 − valence electrons | — | Duplet rule |
| Relative Formula Mass | Mᵣ = Σ Aᵣ | — | Sum of atomic masses |
| Electronegativity Difference | ΔEN = EN₁ − EN₂ | — | Determines bond 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 |
|---|---|---|---|
| Percentage Ionic Character | % ionic ≈ increases with ΔEN | % | No fixed formula at this level |
| Lattice Energy (Qualitative) | ∝ (charge × charge) / distance | — | Higher charge, smaller ions = stronger |
| Melting Point Trend | ∝ strength of bonding | — | Ionic > metallic > simple molecular |
| Boiling Point Trend | ∝ intermolecular forces | — | Stronger forces = higher BP |
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 |
|---|---|---|---|
| Density (Structure) | ρ = m / V | kg m⁻³ | Close packing affects density |
| Electrical Conductivity | Depends on mobile charge carriers | — | Ions (molten/aq), electrons (metals) |
| Bond Energy (Qualitative) | Higher bond energy = stronger bond | kJ mol⁻¹ | No calculation required |
| Intermolecular Forces Strength | IMF ∝ molecular size / polarity | — | Larger = stronger |
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 |
|---|---|---|---|
| Surface Area Effect | Rate ∝ surface area | — | Applies to giant structures |
| Charge Density | Charge density ∝ charge / ionic radius | — | High density = strong attraction |
| Metallic Bond Strength | ∝ number of delocalised electrons | — | More electrons = stronger bonding |
| Covalent Bond Strength | Depends on bond length and bond order | — | Shorter = stronger |
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 |
|---|---|---|---|
| Simple Molecular Forces | Weak intermolecular forces | — | Low MP and BP |
| Giant Ionic Structure | Strong electrostatic attraction | — | High MP, conducts when molten |
| Giant Covalent Structure | Strong covalent bonds | — | Very high MP |
| Metallic Structure | Positive ions + delocalised electrons | — | Conductive, malleable |
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