GCSE Chemistry Topic 2 - Bonds, Structure & Properties of Matter

✅ Part 1: Types of Bonding & Ionic Bonding

🔗 Ionic Bonding

Occurs between metal and non-metal atoms.

• Electron transfer from metal to non-metal
  → Metal forms a positive ion (cation)
  → Non-metal forms a negative ion (anion)

📊 Diagram Suggestion:
Draw Na⁺ and Cl⁻ with dot & cross to show electron transfer.

🧲 Strong electrostatic attraction between oppositely charged ions = strong ionic bond ✅

💎 Properties of Ionic Compounds ✅

• High melting & boiling points – lots of energy needed to break strong bonds

• Conduct when molten or aqueous – ions are free to move and carry charge

• Soluble in water

🎯 Command Word Tip

• Explain = say why + link to structure and bonding

🧠 Think: Why don’t solids conduct?
→ Ions are fixed in a lattice

🧪 Recall Check
Q: Why do ionic compounds only conduct when molten or in solution?
A: Because ions are free to move and carry charge.

✅ Part 2: Covalent Bonding & Metallic Bonding

⚛ Covalent Bonding

Occurs between non-metal + non-metal atoms.

• Atoms share electrons to get full outer shells

• Each shared pair = covalent bond (strong)

🧪 Simple Molecular Substances

• Low melting/boiling points ✅ → only weak intermolecular forces to break

• Do not conduct electricity → no free electrons or ions

• Examples: H₂, CO₂, CH₄

🧠 Think: Why does H₂ have low m.p.?
→ Only weak forces between molecules

🎯 Command Word Tip

• Describe = say what happens

• Explain = give reasons with structure/bonding

💠 Giant Covalent Structures

🔹 Unlike simple molecules, these have strong covalent bonds throughout a 3D network ✅
Examples:

🧪 Metallic Bonding

• Positive metal ions in a sea of delocalised electrons

• Electrons are free to move, so metals conduct electricity

• Strong electrostatic forces = high m.p./b.p.

• Layers of atoms can slide → malleable

🧲 Alloys:
→ Made from different-sized atoms ✅
→ Distort layers and prevent sliding → stronger

🧠 Think: Why is copper a good conductor?
→ Delocalised electrons move and carry charge.

🧪 Recall Check
Q: Why can graphite conduct but diamond can’t?
A: Graphite has delocalised electrons; diamond has none.

✅ Part 3: States of Matter & Physical Changes

🧊 States of Matter

🧠 Think:
Why do particles move faster when heated?
→ Gain kinetic energy

🔁 Changes of State

• Melting / Boiling: Energy used to break forces of attraction

• Condensing / Freezing: Energy released as particles come together

• Temperature stays the same during change

📘 Latent Heat (Grade 8–9):
Energy used to break bonds during change, without increasing temp

🎯 Command Word Tip

• State = name it

• Explain = reason + link to energy/particles

🧪 Quick Quiz
Q: Which state has the weakest forces?
A: Gas

Q: What’s the opposite of sublimation?
A: Deposition

✅ Part 4: Structures & Properties of Substances

🧪 Ionic Compounds

• Strong electrostatic bonds

• High m.p./b.p., only conduct when molten or aqueous

✅ Real-world link:
Used in grit salt for de-icing roads – high melting point helps melt ice

🧪 Simple Molecular Substances

• Weak forces between molecules, NOT between atoms

• Low m.p./b.p., don’t conduct

🎯 Exam Tip:
When asked why it’s a gas/liquid, mention weak intermolecular forces

🧪 Polymers

• Long chains of covalently bonded molecules

• Usually solid at room temp – stronger forces than gases/liquids

🎯 Exam Tip:
State it’s a solid due to intermolecular forces stronger than in gases/liquids ✅

🧪 Giant Covalent Structures

🧪 Fullerenes

• Hollow molecules of carbon (e.g., C₆₀)

• Can form nanotubes – cylindrical fullerenes

✅ Used in nanotechnology and drug delivery due to cage-like shape

🧠 Think: Why are they good for electronics?
→ Conduct + small + strong

🧪 Quick Test
Q: What makes graphite slippery?
A: Weak forces between layers

Q: Why are nanotubes used in electronics?
A: Conduct electricity + strong