Chemistry

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Across
  1. 5. A vertical column in the periodic table.
  2. 7. U,92 atomic number
  3. 9. A pure substance
  4. 13. A horizontal row in the periodic table
  5. 14. The weighted average of all naturally occurring isotopes of an element
  6. 18. The outermost electrons in an atom
  7. 20. H,1 atomic number
  8. 21. The smallest unit of matter that retains the properties of an element.
  9. 25. Elements in Groups 1, 2, and 13–18 of the periodic table
  10. 26. radioactive elements with atomic numbers 89–103
  11. 27. 0
  12. 28. total number of protons + neutrons in one atom.
Down
  1. 1. conduct heat or electricity
  2. 2. fixed distances from the nucleus where electrons are likely to be found
  3. 3. Elements in Group 18 (like helium, neon, argon)
  4. 4. Atoms of the same element with the same number of protons but different numbers of neutrons, giving them different atomic masses.
  5. 6. the atom has a small, dense, positively charged nucleus at its center, with electrons orbiting around it.
  6. 8. Positively charged particles consisting of 2 protons and 2 neutrons
  7. 10. The atom was thought to be a positively charged with negative electrons plums.
  8. 11. −1
  9. 12. Au,79 atomic number
  10. 15. Elements in Group 1 (like lithium, sodium, potassium).
  11. 16. An atom (or group of atoms) that has gained or lost electron
  12. 17. break or shatter easily
  13. 19. Elements in Group 2 (like magnesium, calcium
  14. 22. Ag,47 atomic number
  15. 23. Number of protons in the nucleus.
  16. 24. +1