1											2			3
	4
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		6									7
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	10								11
													12									13
14								15																		16
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18							19																	20					21
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24
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					27																			28
																			29			30					31
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									33																34
															35										36
											37										38

Across 4. tend to lose electrons in chemical reactions, forming positive ions 5. energy stored in the nucleus of an atom 6. reaction in which energy is released 8. neutrally charged subatomic particle 10. needed for a chemical reaction to take place 12. formed when two nonmetals share valence electrons 15. negative effect of using nuclear energy 18. law that states the total mass remains the same in a reaction 20. Formed when an acid and base react 23. reaction in which energy is absorbed 24. acid + base --> salt + water 26. splitting nuclei 27. an atom that has gained or lost electrons 29. equal to the sum of the number of protons and neutrons 33. small number that tells how many atoms of an element are in a compound 36. representation of an object 37. joining nuclei together 38. horizontal row on the periodic table

Down 1. scale at the size of one-billionth of a meter 2. law that states that energy cannot be created or destroyed 3. electrons found on the outer energy level of an atom 6. negatively charged subatomic particle 7. number that tells how many molecules of a compound are present 9. tend to gain electrons in chemical reactions, forming negative ions 11. parts of the atom 13. produces hydroxide ions (OH-) in solution 14. formed when a metal reacts, giving valence electrons to a nonmetal 16. have properties of both metals and nonmetals 17. tool used to organize information about the elements 19. equal to the number of protons 21. positively charged subatomic particle 22. an atom that has gained or lost neutrons 25. new substances made in a chemical reaction 28. produces hydrogen ions (H+) in solution 30. smallest particle of a compound 31. smallest piece of an element 32. part of the atom that contains protons and neutrons 34. one or two letters representing an element 35. vertical column on the periodic table, tells number of valence electrons and determines chemical reactivity