Chemistry Crossword

2. atom that has become electrically charged because it has lost or gained electrons; a positive ion is an atom that has lost one or more electrons;a negative ion is an atom that has gained one or more electrons
3. positively charged particle in the nucleus of an atom
7. Substance that help a reaction speed faster
8. An experiment in which all reactants and all products of a chemical reaction are accounted for
11. substance made of only one kind of matter, which has a unique set of properties
15. When two or substances react to make a new substance
16. smallest part of an element that is representative of that element; a neutral particle made up of a nucleus containing protons and neutrons, and in which the number of electrons equals the number of protons
17. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy
20. group 1 elements in the periodic table, not including hydrogen; the most reactive of the metals
21. new substance produced in a chemical reaction between reactants
23. neutral particle in the nucleus of an atom
24. shiny, malleable, ductile element that conducts electricity

1. slow chemical change that occurs when oxygen in the air reacts with a metal
2. pure substance formed when at least one metal and one non-metal combine
4. An experiment in which one or more products of a chemical reaction can escape
5. dull, brittle element that does not conduct electricity
6. group 18 elements in the periodic table;the most stable and nonreactive elements
9. When a substance state changes, but can be changed back
10. group 2 elements in the periodic table; their reactivity is not as strong as that of the alkali metals
12. Releases heat energy
13. element that has both metallic and non-metallic properties
14. positively charged center of an atom;contains protons and neutrons
18. Absorbs heat energy
19. group 17 elements in the periodic table;the most reactive non-metals
22. catalyst involved in chemical reactions in living things