Crossword Puzzle 10 points

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Across
  1. 2. Basic unit of chemical element
  2. 5. The mass of a single atom
  3. 7. Atom with the same number of protons but different number of neutrons
  4. 10. The number of protons in the nucleus of it's atoms
  5. 11. A subatomic particle with a negative electric charge that is found in all atoms
  6. 13. A horizontal row of elements in the periodic table
  7. 16. An atom or group of atoms that have a positive or negative charge
  8. 17. A pure substance made up of only one type of atom
  9. 19. A negatively charged ion
  10. 21. Positively charged subatomic particle found in nucleus of an atom
  11. 22. A subatomic particle found within the nucleus of an atom
Down
  1. 1. State of matter which particles have no fixed shape or volume
  2. 3. Chemical element that exhibits some metal and some non-metal properties
  3. 4. Specific patterns that are present in the periodic table
  4. 6. A letter or pair of letters used to represent a chemical element
  5. 8. Gas, extremely low reactivity
  6. 9. A form of matter that takes the shape of it's container
  7. 12. An ion with a positive charge
  8. 14. Lustrous, good conductors of heat and electricity
  9. 15. Substance that maintains it's own shape and volume
  10. 18. Anything that has mass and takes up space
  11. 20. A column in the periodic table