Atomic History & Structure

1. one of the first to propose the existence of atoms
3. the smallest part of an element that retains the properties of that element
5. the experiment that discovered electrons
7. subatomic particles with no charge
8. atoms with the same number of protons but different numbers of neutrons
11. positively charged subatomic particles
12. the number of protons in the nucleus of an atom
15. developed the first atomic theory with 4 parts
17. subatomic particle with a negative charge
18. the weighted average mass of atoms in a naturally occurring sample of an element
21. atomic model proposed by Rutherford
22. isotope of hydrogen with one proton and no neutrons in the nucleus
23. one twelfth the mass of a carbon 12 atom

2. his experiment lead to the discovery of the neutron
4. discovered canal rays moving opposite cathode rays leading to the discovery of the proton
6. hydorgen-2 isotope
9. isotope of hydrogen with one proton and two neutrons
10. atomic model proposed by Thomson
13. the scientist responsible for the gold foil experiment
14. metal disks that conduct electric current
16. the core of an atom that contains most of the atom's mass
19. developed the oil-drop experiment that determined the electron charge and mass
20. number of protons and neutrons in the nucleus of an atom