Atoms revision

2. Number – The number of protons in the nucleus of an atom.
5. – A substance made when two or more elements join chemically.
10. – A negatively charged particle that moves around the nucleus in shells.
12. Gases – Unreactive gases found in Group 0 (e.g. helium, neon, argon).
13. – A pure substance made of only one type of atom.
14. Metals – Elements in Group 1 that are very reactive metals (e.g. sodium, potassium).
16. – A particle with no charge found in the nucleus.

1. – Reactive non-metals found in Group 7 (e.g. chlorine, bromine, iodine).
3. – An element that conducts heat and electricity, is shiny, and can be shaped.
4. – An element that is dull, often a gas, and does not conduct heat or electricity well.
6. – The centre of the atom containing protons and neutrons.
7. – A positively charged particle found in the nucleus of an atom.
8. – Two or more substances combined but not chemically joined.
9. – A column in the periodic table; elements in the same group have similar properties and the same number of outer electrons.
11. – A row in the periodic table; elements in the same period have the same number of electron shells.
15. – The smallest particle of a substance that cannot be seen with the naked eye.