Across
- 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
Down
- 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