Chemistry

3. most stable and unreactive
4. average mass of an element in atomic mass units
6. a slow chemical change that occurs when oxygen in the air reacts with a metal
7. description of how a substance interacts with other substances, such as acid
13. less reactive than alkaline metals
16. represents the number of atoms
19. pure substance formed when at least one metal and one non-metal combine
20. invisible negatively charged charged particle that orbits the nucleus of an atom
22. releases heat energy
23. absorbs heat energy

1. most reactive non-metals
2. group of atoms acting as one
5. a compound formed when two non-metals combine
6. a chemical reaction that takes place in the cells in your body
8. positively charge particle of an atom
9. number of protons in an atom
10. organic catalyst
11. combination of symbols that represent a compound
12. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and gives off energy
14. most reactive metals in the periodic table
15. atoms that has become electrically charged because it has lost or gained electrons
17. results from a chemical reaction
18. neutral particle of the nucleus of an atom
21. cloudy mixture in which tiny particles of one substance are within another and particles cannot be separated.
24. invisible negatively charged particle that orbits the nucleus of an atom