Chemistry Unit 2

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Across
  1. 2. What principle states that electrons occupy orbitals of lowest energy first?
  2. 7. All atoms are electrically ________
  3. 8. The _______ number shows the # of protons and electrons
  4. 10. When an electron has its lowest possible energy, what state is the atom in?
  5. 12. What has the highest energy on an electromagnetic spectrum?
  6. 13. What is the smallest particle of an element?
  7. 16. What is it called when particles and rays emitted from the radioactive source?
  8. 17. What attractive force holds the nucleus together?
  9. 19. What are the horizontal rows on a periodic table called?
  10. 20. Alkali Metals are found in which group?
  11. 21. __________ are negatively charged and are massless
Down
  1. 1. The vertical columns on a periodic table are called ________.
  2. 3. _________ are positively charged and have a mass of 1 amu
  3. 4. This region of the atom contains protons and neutrons; dense and is positively charged
  4. 5. This scientist discovered the neutron
  5. 6. What makes up 80% of the periodic table?
  6. 9. What has the lowest energy on an electromagnetic spectrum?
  7. 11. The _________ is a wave's height from zero to crest
  8. 14. The longer the distance of a ________ is, the lower the energy.
  9. 15. This scientist has a model named after him
  10. 18. What nuclear radiation emits helium nuclei?