"Atoms & Molecules": HTML5 Crossword

Across

7. this subatomic particle has a neutral charge (7)
8. this subatomic particle is outside the nucleus (8)
9. 2 atoms bonded together (8)
11. the symbol "He" stands for this (6)
12. the # of protons in an atom (12)
15. what science is the study of matter? (9)
16. the symbol "O" stands for this (6)
17. this orbits the nucleus (8)
20. anything that has mass or volume (6)

Down

1. chart that organizes all of the elements (13)
2. 2 or more atoms bonded together (8)
3. the symbol "H" stands for this (8)
4. one of the three states of matter (5)
5. meaning of atoms (10)
6. the amount of space that a substance or an object takes up (6)
10. a measure of the amount of matter in a substance or object (4)
13. a proton has this charge (8)
14. where you can find protons & neutrons (7)
18. a cloud that is used to hold electrons outside of the nucleus (7)
19. how many parts to an atom (5)