MM 1 revision

5. Chemical compounds that change colour according to the pH of the solution it is in.
7. Involving a net absorption of energy
10. Negative particles found outside the nucleus of an atom.
12. A chemical formula that shows the ratio of the number of atoms in a compound. ________ formula.
14. Atoms of the same element which have different numbers of neutrons in their nuclei.

1. The point at which a reversible reaction takes place at exactly the same rate in both directions.
2. Vertical columns of elements in the periodic table.
3. Horizontal rows of elements in the periodic table
4. A substance that speeds up the rate of another reaction but is not used up or changed itself.
6. A solid material produced from a solution
8. One of the six unreactive gases found in group 0 of the periodic table. They have a complete outer shell of electrons, e.g. neon, argon, helium. _______ gases.
9. A substance that contains water
11. Bond formed when atoms join together by sharing electrons. _______ bonds.
13. The mass of an atom compared with an atom of C. This is usually the same as or very similar to the mass number of the element. _________ atomic mass.