Matter Crossword Puzzle

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Across
  1. 1. Formed when an atom loses one or more electrons
  2. 4. Elements in a row on the periodic table with one proton variation
  3. 6. Elements that almost never react with other elements
  4. 7. The rare earth elements with atomic numbers 58-71
  5. 8. A space in which electrons move around the nucleus
  6. 9. Positively charged particles
  7. 12. Formed when an atom gains one or more electrons
  8. 14. The measurement used for protons and neutrons (mass)
  9. 15. The most reactive elements on the periodic table
  10. 21. Very reactive metals that play a part in day to day human life
  11. 23. An element with properties opposite to those of a metal
  12. 24. Elements that are less reactive, and are some of the earliest known to man
  13. 25. An element with properties of metals and nonmetals
Down
  1. 2. An atom of the same element with a different number of neutrons
  2. 3. An element that conducts electricity/heat well, and has a shiny appearance
  3. 5. Uncharged/neutral particles
  4. 10. The process in which atoms produce energy and particles
  5. 11. Formed when an atom loses or gains one or more electrons
  6. 13. Found in the center of the atom, contains protons and neutrons
  7. 16. Negatively charged particles
  8. 17. The process of a radioactive atom changing its identity
  9. 18. Elements in a column on the periodic table with similar properties
  10. 19. Very reactive nonmetals that easily form compounds called salts with many metals
  11. 20. Elements on the periodic table that are metallic and radioactive, with the atomic numbers 90-103
  12. 22. Number of protons in the nucleus of an element