crossword puzzle

1. positively charged particle
4. atoms of the same element that have a different number of neutrons
5. metals, group 1 periodic table metals that are very reactive
9. cloud, group of electrons circulating around a nucleus
10. (inert) gases, gases that almost never reactive with other metals
12. metals, group 2 periodic table metals that are more reactive then most other metals
15. uncharged particle
16. the elements in a column of the periodic table
17. very reactive nonmetals in group 17 of the periodic table that form compounds called salts with other metals
18. 90-103 elements that are set apart from the rest of the periodic table
19. ion, an atom that is larger then an atom that formed it
20. decay, the change in the number of protons of an atom
22. the total number of protons and neutrons in an atoms nucleus
23. metals, elements in group 3-2 of the periodic table that are less reactive than most other metals
24. combination of a proton and neutron

1. ion, an atom that is smaller than the atom that formed it
2. number, identity of an atom determined by the number of protons in its nucleus
3. elements that have properties of both metals and nonmetals
6. are rare earth metals that are actually not that rare
7. an atom that gained or lost electrons
8. shiny and solid element that conduct electricity and heat well
11. elements on the right side of the periodic table that are gases or liquids
13. each horizonal row in a periodic table
14. the process by which atoms produce energy and particles
21. negatively charged particle that moves around the nucleus