There is a fourth state of matter called plasma, found in extremely hot environments like sun. Suggest why Dalton did not include this form in his atomic theory.

The diagrams given below use different coloured spheres to represent the atoms of different elements. Use these terms to describe what each of the diagrams represent:

pure substance, mixture, atom, molecule, element, compound

Predict whether the matter of the familiar materials in the table is likely to be pure, and which are likely to be mixtures.