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Ch. 13 Models of Atoms. J.J. Thomson. “Plum pudding” atom negatively charged e - stuck into a lump of positively charged material – similar to chocolate chip cookies. “The Blow Pop”. Ernest Rutherford
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J.J. Thomson “Plum pudding” atom negatively charged e- stuck into a lump of positively charged material – similar to chocolate chip cookies
“The Blow Pop” Ernest Rutherford In Rutherford’s gold foil experiment he discovered electrons surround a dense positive nucleus.
Bohr Model electrons are arranged in fixed orbits around the nucleus, called electron shells. Like planets revolving around the sun. ex. Orbits gum
Bohr Model cont. • Electrons found in the shells: 1st shell can have up to 2e- 2nd shell can have up to 8e- 3rd shell can have up to 18e- 4th shell can have up to 32e- • The outermost shell cannot have more than 8e- (atoms bond with other atoms to try to get 8e- in their outermost shell).
Quantum Mechanical Model • Quantum mechanics was developed by Erwin Schrodinger • Estimates the probability of finding an e- in a certain position • Electrons are found in an “electron cloud”