Chemistry Crossword

3. A catalyst involved in chemical reactions in living things
7. Group 1 elements in the periodic table, not including hydrogen; the most reactive of the metals
8. A pure substance formed when at least one metal and one nonmetal combine
10. Ability of a substance to conduct electricity
12. A mixture that you can see the different substances clearly/the different substance that make up the substance are visible
15. Group 17 elements in the periodic table; the most reactive non-metals
17. An experiment in which all reactants and all products of a chemical reaction are accounted for
19. An invisible negatively charged particle that orbits the nucleus of an atom
20. A chemical reaction that occurs when oxygen reacts violently with a substance to form a new substance and gives off exothermic energy
21. A cloudy mixture that the tiny particles of one substance is held within each other, and the particles cannot be separated from each other
22. Mass of one atom of an element calculated from the total number of protons, neutrons and electrons of that atom. Measured in amu
24. A vertical column of elements in the periodic table

1. An atom/group of atoms that has become electrically charged because it has lost/gained electrons
2. A pure substance that cannot be broken down into other substances; substance made up of only one type of atom
4. A steady flow of charged particles
5. A change that results when two or more substances react to create a different substance of unique properties
6. The number of protons and electrons in the nucleus of one atom of an element
7. Group 2 elements in the periodic table: their reactivity is not as strong as that of an alkali metal
9. The smallest part of an element that is representative of that element; a neutral particle made up of a nucleus that contains protons/neutrons and electrons
10. A reaction that takes place when two or more substances react to form a new substance of unique properties
11. The positively charged centre of an atom that contains protons and neutrons
13. Combination of symbols that represent a compound: the formula identities the elements in a compound and the amount of each element
14. A material that electricity can move through easily
16. Group 18 elements in the Periodic Table of Elements that are the most stable and non reactive non-metal
18. A chemical combination of two or more elements in a specific ratio
23. substance that helps a chemical reaction to proceed more quickly