Chemistry Crossword

2. an experiment in which all reactants and all products of a chemical reaction are accounted for
3. combination of symbols that represent a compound
5. chemical combination of two or more elements in a specific ratio
8. number of protons in the nucleus of one atom of an element
9. mass of one atom of an element calculated from the total number of protons, neutrons, and electrons of that atom
11. the most reactive non-metals
12. group 2 elements in the periodic table; their reactivity is not as strong as that of the alkali metals
13. vertical column of elements in the periodic table that have similar chemical properties
15. the mass of the products always equals the mass of the reactants
16. substance that helps a chemical reaction to proceed more quickly
18. chemical reaction that releases energy
19. atom that has become electrically charged because it has lost or gained electrons
22. orbit of electrons around the nucleus of an atom
24. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy

1. catalyst involved in chemical reactions in living things
2. a reaction that takes place when two or more substances react to form new substances
4. slow chemical change that occurs when oxygen in the air reacts with a metal
6. group 1 elements in the periodic table, not including hydrogen; the most reactive of the metals
7. chemical reaction that absorbs energy
10. change that results when two or more substances react to create a different substance or substances
14. cloudy mixture in which tiny particles of one substance are held within another and particles cannot be separated out from the other substance
17. energy stored in chemicals and released when chemicals react
20. invisible negatively charged particle that orbits the nucleus of an atom
21. pure substance that cannot be broken down into other substances
23. compound that dissolves in water to form a solution with a pH lower than 7