CONCEPT OF THE ATOM

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Across
  1. 4. Elements formed inside stars
  2. 7. Positively charged atom
  3. 8. Fundamental particle that makes up protons and neutrons
  4. 12. Cloud-like region where electrons are found
  5. 15. Unstable atoms that emit radiation
  6. 20. Process of forming elements inside stars
  7. 22. Anything that has mass and occupies space
  8. 24. Atoms that gain or lose electrons
  9. 25. Positively charged particle in the nucleus
  10. 26. The force that holds protons and neutrons together in the nucleus
  11. 27. Total number of protons and neutrons in an atom
  12. 28. Elements arranged by increasing atomic number
  13. 30. Energy released from splitting or fusing atomic nuclei
Down
  1. 1. Model that describes how electrons occupy energy levels
  2. 2. Vertical columns in the periodic table
  3. 3. Father of the modern periodic table (last name)
  4. 5. The building blocks formed after the Big Bang
  5. 6. Negatively charged particle in an atom
  6. 9. Process where two light nuclei combine to form a heavier one
  7. 10. The outermost electrons involved in bonding
  8. 11. Atoms of the same element with different numbers of neutrons
  9. 13. Splitting of a heavy atomic nucleus
  10. 14. Heaviest part of the atom, located at the center
  11. 16. Unit used to measure the mass of protons and neutrons
  12. 17. The number of protons in an atom
  13. 18. Basic unit of matter
  14. 19. Horizontal rows in the periodic table
  15. 21. Subatomic particle with no charge
  16. 23. Element with atomic number 92
  17. 29. Scientist who proposed an early atomic theory