Untitled Flashcards Set

John Dalton (1805) said atoms are indivisible (smallest particles) and had the solid sphere model in the early 1800s. He also said all atoms of an element are identical (this is not true)

2. JJ Thompson gave the plum pudding model in the late 1800s that showed the electrons as the “plums” but could not account for the protons

3. Robert Millikan (1909) did the oil drop experiment and discovered the charge of an electron and found they are negatively charged

4. Rutherford’s model (1911) discovered the nucleus and protons and that it was positively charged particles called protons make the nucleus positively charged using the gold foil experiment. This showed the gold atoms had lots of empty space and that the particles were only defelected when they hit the nucleus

5. James Chadwick (1932) discovered the neutrons in the nucleus because there was unaccounted mass in the nucleus that had no charge where he proved this in his beryllium paraffin wax

6. Bohr had the “final model” that displayed the electron shells but did not account for why the electrons were in rigid shells

7. Quantum model- claims electrons are NOT in fixed shells and instead are in certain regions of space at any given time and act as “clouds”