Science Test 6

2. whenever a substance reacts rapidly with oxygen
3. opposite charges
6. tiny group of two or more atoms that are bonded tightly together
8. hold a positive charge
10. hold a negative charge
13. tiny particles of which all matter is composed
15. substance composed of more than one type of atom bonded together
18. 99% of earth's atmosphere
19. electrons in orbit at the same distance from the nucleus
22. substances composed of one type of atom
23. the measure of the pull of gravity on an object
26. amount of matter that makes up an object
27. the periodic table is divided into ___ groups: Metals, Metalloids, and Nonmetals
28. Dmitri Mendeleev created the ____________

1. scientists who study chemistry
4. atoms of elements or compounds are rearranged to form substances
5. most common alkaline earth metal
7. a basic building block of the complex compounds found in your body
9. unit used to measure mass
11. number of protons in an atom
12. like charges
14. study of what substances are made of and how one substance can be changed into another
16. the amount of matter in one unit of volume
17. dense core of an atom
20. anythings lacking in electrical charge
21. hold no charge
24. anything that takes up space and has mass
25. only liquid metal