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