Crossword puzzle

3. atoms of the same element that have a different number of neutrons
4. group 1 periodic table metals that are very reactive
6. combination of a proton and neutron
8. elements on the right side of the periodic table that are gases or liquids
11. shiny and solid element that conduct electricity and heat well
12. the process by which atoms produce energy and particles
15. elements in group 3-2 of the periodic table that are less reactive than most other metals
16. elements that have properties of both metals and nonmetals
19. uncharged particle
20. gases that almost never reactive with other metals
23. positively charged particle
24. each horizonal row in a periodic table
25. 90-103 elements that are set apart from the rest of the periodic table

1. the change in the number of protons of an atom
2. cloud group of electrons circulating around a nucleus
5. are rare earth metals that are actually not that rare
7. an atom that is smaller than the atom that formed it
9. group 2 periodic table metals that are more reactive then most other metals
10. an atom that is larger then an atom that formed it
13. the total number of protons and neutrons in an atoms nucleus
14. very reactive nonmetals in group 17 of the periodic table that form compounds called salts with other metals
17. identity of an atom determined by the number of protons in its nucleus
18. the elements in a column of the periodic table
21. negatively charged particle that moves around the nucleus
22. an atom that gained or lost electrons