Chemistry crossword

2. (in chemistry) vertical column of elements in the periodic table; elements in a family all have similar chemical properties; also called a group.
3. change of state from a solid to a liquid.
6. group 18 elements in the periodic table;the most stable and unreactive elements.
9. change that results when two or more substances react to create a different substance or substances; the new substances have completely different properties from the original ones.
13. group 1 elements in the periodic table, not including hydrogen; the most reactive of the metals.
16. mass of one atom of an element calculated from the total number of protons,neutrons, and electrons of that atom; measured in atomic mass units .
18. amount of mass in a given volume of a substance.
21. vertical column of elements in the periodic table; elements in a family all have similarchemical properties; also called a family.
22. a material that electric charge can move through easily.
23. compound that dissolves in water to form a solution with a pH lower than 7.

1. group 17 elements in the periodic table;the most reactive non-metals.
4. ability of a substance to conduct electricity or heat.
5. energy stored in chemicals and released when chemicals react; a form of potential or stored energy .
7. shiny, malleable, ductile element thatconducts electricity.
8. colourless, odourless gas;produced by incomplete combustion of chemicals containing carbon (e.g. hydrocarbons); major source: motor vehicles.
10. conductor through which electric current enters or leaves a device or material.
11. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy.
12. the sum of the number of protonsand neutrons in an atom.
14. element that has both metallic and non-metallic properties.
15. positively charged centre of an atom;contains protons and neutrons.
17. chemical combination of two or more elements in a specific ratio.
19. pure substance that cannot be broken down into other substances; substance made up of only one type of atom.
20. neutral particle in the nucleus of an atom.