Year 8 Unit 2

2. – The number of protons in the nucleus of an atom (and also the number of electrons in a neutral atom).
5. – The very reactive metals in Group 1 of the periodic table (e.g. lithium, sodium, potassium).
6. – A column down the periodic table; elements in a group have similar properties.
8. – A way of showing the elements in a compound and how many atoms of each (e.g. H₂O).
10. – A particle in the nucleus of an atom with no charge (neutral).
12. – Two or more substances that are not chemically joined together and can be separated.
14. – A tiny particle with a negative charge that moves around the nucleus of an atom.
16. – A list of metals (and carbon/hydrogen) arranged in order of how reactive they are.
21. – A reaction where a more reactive element takes the place of a less reactive element in a compound.
22. – A substance made when two or more different elements are chemically joined together.

1. – A chart that organises all the elements in order of their atomic number and properties.
3. – The reactive non-metals in Group 7 of the periodic table (e.g. chlorine, bromine, iodine).
4. – A particle in the nucleus of an atom with a positive charge.
7. – A row across the periodic table.
9. – How easily and quickly an element reacts with other substances.
11. – The unreactive gases in Group 0 of the periodic table (e.g. helium, neon, argon).
13. – A pure substance made of only one type of atom.
15. – The new substances made in a chemical reaction.
17. – The lightest element, with one proton and one electron; found in Group 1 of the periodic table.
18. – The total number of protons and neutrons in the nucleus of an atom.
19. – The substances you start with in a chemical reaction.
20. The smallest particle of an element that still has the properties of that element.