UNIT 2 OF SCIENCE WORLD

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Across
  1. 2. Wilhem Roentgen discovered________.
  2. 7. The ion with negative charge.
  3. 9. The probable distribution of electrons around the nucleus among the orbitals is called ___________.
  4. 13. An atom in which the total no. of electron& the total no. of protons are not equal.
  5. 14. Dalton ____ come up with atomic theory.
  6. 15. He divided matter into 4 elements.
  7. 16. It is located at the center of an atom.
  8. 18. They are usually illustrated as electron clouds.
  9. 19. Has the electric configuration 1s2,2s2,2p6.
  10. 20. Has the electric configuration 1s7.
Down
  1. 1. Protons+Neutron=________.
  2. 3. He proposed that all substance are composed of 4 elements.
  3. 4. ____ materials cause atoms to break down spontaneously.
  4. 5. It has electrical charge of -1.
  5. 6. The highest occupied energy level or electron shell is called______.
  6. 8. He constructed the fore runner of the Modern TV picture tube in the 1870s.
  7. 10. The ion with positive charge.
  8. 11. It has no net electric charge.
  9. 12. It is a german word for building up or construction.
  10. 17. It has an electrical charge of positive one.