C1 atomic structure

All substances are made of atoms. An atom is the smallest part of an element that can exist.

an element is a substance which only contains one type of atom

a compound is a substance which contains atoms from 2 or more elements which are chemically combined in fixed proportions

+1 they are positively charged

-1 they are negatively charged

0 they are neutral

two or more elements or compounds not chemically combined together

Filtration is used to separate an insoluble solid from a liquid. It is useful for separating sand from a mixture of sand and water, or excess reactant from a reaction mixture.

Crystallisation is used to produce solid crystals from a solution. When the solution is warmed, some of solvent evaporates leaving crystals behind. For example, crystallisation is used to obtain copper sulfate crystals from copper sulfate solution.

put the solution in an evaporating basin warm the solution by placing the evaporating basin over a boiling water bath stop heating when crystals begin to form around the edge of the basin

Simple distillation is used to separate a solvent from a solution

Simple distillation works because the dissolved solute has a much higher boiling point than the solvent. When the solution is heated, solvent vapour leaves the solution. It moves away and is cooled and condensed. The remaining solution becomes more concentrated as the amount of solvent in it decreases.

Fractional distillation is used to separate different liquids from a mixture of liquids.

Paper chromatography is used to separate mixtures of soluble substances. These are often coloured substances such as food colourings, inks, dyes or plant pigments.

Before the discovery of the electron, atoms were thought to be tiny spheres that could not be divided.

thomsons discovery of the electron led to the plum pudding model of the atom. The plum pudding model suggested that the atom is a ball of positive charge with negative electrons embedded in it

The results from the alpha particle scattering experiment led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged. This nuclear model replaced the plum pudding mode

the atomic number

mass number - atomic number

1 x 10-10 m

1 x 10-14 m

1

1

very small