Chemistry Crossword

2. orbit of electrons around the nucleus of an atom
3. an experiment in which all reactants and all products of a chemical reaction are accounted for
4. change that results when two or more substances react to create a different substance or substances
6. group 2 elements in the periodic table; their reactivity is not as strong as that of the alkali metals
9. the mass of the products always equals the mass of the reactants
10. energy stored in chemicals and released when chemicals react
14. mass of one atom of an element calculated from the total number of protons, neutrons, and electrons of that atom
15. chemical reaction that releases energy
16. cloudy mixture in which tiny particles of one substance are held within another and particles cannot be separated out from the other substance
18. invisible negatively charged particle that orbits the nucleus of an atom
20. vertical column of elements in the periodic table that have similar chemical properties
22. a reaction that takes place when two or more substances react to form new substances
24. number of protons in the nucleus of one atom of an element
25. catalyst involved in chemical reactions in living things

1. combination of symbols that represent a compound
5. group 1 elements in the periodic table, not including hydrogen; the most reactive of the metals
7. chemical reaction that absorbs energy
8. atom that has become electrically charged because it has lost or gained electrons
11. slow chemical change that occurs when oxygen in the air reacts with a metal
12. pure substance that cannot be broken down into other substances
13. chemical combination of two or more elements in a specific ratio
17. substance that helps a chemical reaction to proceed more quickly
19. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy
21. compound that dissolves in water to form a solution with a pH lower than 7
23. the most reactive non-metals