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Chemistry - Coggle Diagram
Chemistry
Elements
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Can exist as single atoms (monatomic), in clusters (molecules) or large grid-like structures (lattices)
Monatomic elements
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Very rare in nature e.g helium, neon, argon, krypton
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Examples include helium (used in party balloons because it is lighter than air), neon (used in neon lights creating coloured signs) and argon (used in incandescent light bulbs and stops the filament from burning. It is a noble gas, meaning it is unreactive)
Molecular elements
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All molecules are identical (same size, shape, number of atoms and type)
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Lattices
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Non-metallic lattices
Only few non-metallic atoms form lattices e.g carbon, which forms a crystal lattice which could form substances like graphite or diamond
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In graphite, the atoms bonded together in sheets that can slide over one another making graphite a good lubricant
In diamonds, the carbon atoms are strongly bonded to each other in four directions which is why diamonds are the hardest natural substance on Earth.
Way atoms are arranged in element determines many physical properties of element (state of matter, melting point, boiling point, conduction of electricity and strength of substance)
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Physical changes
Usually considered as
Changes of state
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Some solids do not change to a liquid when they are heated. Instead they turn straight into a gas in a process called sublimation
When a solid is heated, its particles gain more energy and vibrate more
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Changes caused by mixing
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Contain particles that are all exactly the same e.g. salt, gold, distilled water, carbon dioxide gas are all pure substances
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Can be solids, liquids or gases
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Example is cement; its strength depends on proportions of cement, sand and gravel
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Physical change is where no new substance is produced during the change. The physical changes include a change in shape or form, expansion and contraction, a change of state (solids, liquids or gas) or mixing substances together. The physical properties of the substance may change but no new substance is formed.
Chemical changes
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Examples
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Produces light, sound, gas
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