science

2. average mass of an atom
4. the mass of a chemical elements single atom
9. atomic theory originated as a philosophical concept in ancient india and greece
10. russian chemist and inventor
12. group of rare gases that include helium neon argon kyrypton
14. sharing of electrons between 2 or more atoms
15. negatively charged ion
17. positively charged ion
19. are electrons that are located in the outermost electron shell of an atom

1. any of six nonmetallic elements that constitute group 17
3. A stable subatomic particle with a positive electric charge
5. two or more types of atoms that have the same atooic # and position in the periodic table
6. A subatomic particle whose electric charge is negative
7. atom structure The structure of an atom comprising a nucleus in which the protons and neutrons are present
8. if there are more than protons in a piece of matter it will have a negative charge, if there are fewer it will be positive charge.
11. when two or more ions come together and held together
13. atom or molecule with net charge due to loss/gain of one or more electron
16. A subatomic particle or about the same mess as a proton but without an electric charge
18. Any substance that has mass and takes up space by having volume