Topic A - atomic theory

SL/HL

element

• a pure substance - can’t be broken down into simpler substance by chemical means

compound

• pure substance formed by 2/more diff elements - chemically joined in a fixed ratio

• have diff properties from the elements they’re made of

mixture

• contain more than one elements and/or compound - not chemically bonded

• retain their individual properties

heterogenous mixture

• mixture of visibly different substances / phases

• e.g. sand and water

homogenous mixture

• same uniform appearance & composition throughout

• e.g. salt solution

solvation

• involves formation of ion-dipole forces between a solute and a solvent

filtration

• separation technique

• used to separate heterogeneous mixtures

recrystallisation

• purification technique

• used to purify a solid

evaporation

• separation technique

• used to separate a homogenous mixture

distillation

• separation technique

• used to separate 2 miscible liquids with diff boiling points

chromatography

• separation technique

• used to separate mixture of solutes in a solvent