Chemistry Crossword

3. combination of pure substances
4. group 18 elements in the periodic table;the most stable and unreactive elements
6. change in the appearance or state of a substance that does not change the composition
11. group 17 elements in the periodic table;the most reactive non-metals
12. vertical column of elements in the periodic table
14. chemical reaction that releases energy
16. a table in which the elements are organized by their physical and chemical properties
17. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy
18. cloudy mixture in which tiny particles of one substance are held within another and particles cannot be separated out from the other substance
19. pure substance formed when at least one metal and one non-metal combine
24. cloudy mixture in which tiny particles of one substance are held within another, and the particles can be separated out
25. catalyst involved in chemical reactions in living things

1. change that results when two or more substances react to create a different substance or substances
2. neutral particle in the nucleus of an atom
5. heterogeneous mixture;mixture in which the different substances that make up the mixture are visible
7. substance made of only one kind of matter, which has a unique set of properties
8. chemical reaction that absorbs energy
9. substance that strongly resists the flow of electricity
10. substance that reacts with another substance or substances in a chemical reaction to create new substances with different properties
13. pure substance formed when non-metals combine
15. positively charged particle in the nucleus of an atom
20. an experiment in which one or more products of a chemical reaction can escape
21. substance that helps a chemical reaction to proceed more quickly
22. element that has both metallic and non-metallic properties
23. description of a substance that can be pounded or rolled into sheets