New Way Chemistry for Hong Kong A-Level Book 11

Chapter 12Chapter 12Structures and Properties of Structures and Properties of

MaterialsMaterials

12.112.1 Classification of Substances Classification of Substances

According to StructureAccording to Structure

12.2 12.2 Classification of Substances Classification of Substances

According to the Nature of BondingAccording to the Nature of Bonding

New Way Chemistry for Hong Kong A-Level Book 12

Some Pre-knowledge

solid

Particles (may be molecules, ions or metallic atoms)

forces of attraction between particles weaken

liquid

gas

forces of attraction between particles broken

12.1 Classification of Substances According to Structures (SB p.277)

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12.1 Classification of Substances According to Structures (SB p.278)

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Simple Molecular StructuresExamples

forces of attraction between particles weaken

(by raising the temp.)

forces of attraction between particles broken

(by further raising the temp.)

solid iodine(at room temp.)solid iodine

(at room temp.)

liquid iodineliquid iodine

Gaseous iodineGaseous iodine

12.2 Classification of Substances According to the Nature of Bonding (SB p.279)

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Simple Molecular StructuresExamples

solid chlorine(at room temp.)solid chlorine

(at room temp.)

liquid chlorineliquid chlorine

gaseous chlorine(at room temp.)

gaseous chlorine(at room temp.)

forces of attraction between particles strengthen

(by lowering the temp.)

(by further lowering the temp.)

forces of attraction between particles weaken

12.2 Classification of Substances According to the Nature of Bonding (SB p.279)

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12.2 Classification of Substances According to the Nature of Bonding (SB p.280)

Properties of simple molecular substances

1. Low melting points and boiling points

2. Soft and easily distorted

3. Non-conductors of electricity

4. Usually insoluble in oplar solvents but soluble in non-polar solvents

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Macromolecular Structures

Substances with macromolecular structures consist of very large molecules containing thousands of atoms.

12.2 Classification of Substances According to the Nature of Bonding (SB p.281)

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Giant Structures

Substances with giant covalent structure (graphite), giant ionic structure (sodium chloride) and giant metallic structure (copper)

Graphite(giant covalent

structure)

12.2 Classification of Substances According to the Nature of Bonding (SB p.280)

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Giant covalent structures

diamond and silicon(IV) oxide (quartz)

12.2 Classification of Substances According to the Nature of Bonding (SB p.279)

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Giant covalent structures

The giant covalent structures of graphite ( a layered structure)

12.2 Classification of Substances According to the Nature of Bonding (SB p.279)

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12.2 Classification of Substances According to the Nature of Bonding (SB p.281)

Properties of giant covalent substances

1. High melting points and boiling points

2. Hard and rigid

3. Poor conductors of heat and electricity

4. Insoluble in any solvent

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12.2 Classification of Substances According to the Nature of Bonding (SB p.281)

Properties of ionic compounds

1. High melting and boiling points

2. Hard but brittle

3. Good conductors of electricity in molten or aqueous state

4. Soluble in polar solvents but insoluble in non-polar solvents

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12.2 Classification of Substances According to the Nature of Bonding (SB p.283)

Properties of metals

1. High melting and boiling points

2. Good conductors of heat and electricity

3. High density

4. Malleable and ductile

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The END