1.1 Bonding: the structure of matter
Element: a substance that cannot be split into anything simpler, in a chemical reaction. Each element has a unique proton number.
Mixture: two or more elements mixed together BUT that are not chemically combined Compound: a substance in which two or more different elements are chemically combined. Metals:
- strong
- malleable and ductile
- sonorous
- good conductors of heat and electricity
- have high melting and boiling points (except mercury)
- high density
- react with oxygen to form (usually) basic compounds called metal oxides (aluminium oxide is amphoteric)
- in reactions they form positive ions (cations)
- some, g. iron, are magnetic.
Non metals:
- Are brittle
- Have lower melting and boiling points than metals
- Poor conductors of electricity, except for graphite (carbon) and are also bad conductors of heat
- Have low densities
- Most react with oxygen to form (usually) acidic oxides (carbon monoxide is neutral)
- Form negatively charged ions (anions) in a chemical reaction
Alloy: a mixture where at least one other substance is added to a metal, to improve its properties; the other substance is often a metal too (but not always) e.g. brass (70% copper and 30% zinc) is harder than copper, does not corrode, used in musical instruments.