lived in Abdera, Greece but not much known about his early life
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what inspired Democritus’ model?
Parmenides’ challenge saying that all matter is in a state of not being or being
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what did Democritus’ model show?
all atoms are tiny indivisible particles that move using hooks and barbs, are infinite in number and variation of size and shape, and cause properties of substances
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was Democritus’ model accepted?
no
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when did John Dalton live?
1766-1844
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what was Dalton’s background?
English chemist and physicist who previously studied meteorology in manchester
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what inspired Dalton’s model?
he set out to scientifically prove Democritus’ model
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what are Dalton’s five tenets?
1. all matter is composed of atoms 2. atoms of elements are the same 3. atoms are indivisible and neither created or destroyed 4. atoms of separate elements can combine in simple whole-number ratios to form compounds 5. in chemical reactions, atoms are combined, separated, or rearranged
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was Dalton’s model accepted?
it was a start but did not talk much about the atoms themselves
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when did Lord Kelvin live?
1824-1907
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what was Lord Kelvin’s background?
lived in Belfast, Ireland, originally named William Thomson, studied as a mathematician, physicist, and engineer
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what inspired Lord Kelvin’s model?
the movement of smoke rings like a vortex and sailor knots
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what did Lord Kelvin’s model show?
atoms twist and turn like knots
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was Lord Kelvin’s model accepted?
it was forgotten due to his more famous inventions like the Kelvin absolute temperature scale and the mariner compass and also because he had no scientific proof
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when did J.J. Thomson live?
1856-1940
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what was Thomson’s background?
originally wanted to be an engineer but had financial issues and became a physicist at Owen’s college who liked to tinker around with stuff
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what inspired Thomson’s model?
his cathode ray experiment finding corpuscles or electrons and plum pudding
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what did Thomson’s model show?
atoms contained negative particles floating within a soup of diffuse positive charge
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was Thomson’s model accepted?
his model was soon found to have many problems including no nucleus
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when did Robert Millikan live?
1868-1953
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what was Robert Millikan’s background?
lived in Morrison, Illinois in a rural community, studied mathematics at Oberlin College and worked with optics, molecular physics and electricity
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what inspired Millikan’s model?
his water and oil drop experiments
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what does Millikan’s model show?
concrete proof of electron’s negative charge and the amount of charge in an electron
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was Millikan’s model accepted?
yes because he had concrete proof
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when did Ernest Rutherford live?
1871-1937
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what was Rutherford’s background?
lived in rural spring grove, new zealand as the one of 12 kids, was interested in science at a young age, studied at canterbury college and worked in cavendish’s lab
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what inspired rutherford’s model?
his gold foil experiment
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what did rutherford’s model show?
determined the presence of the nucleus
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was rutherford’s model accepted?
yes except no reason for why electrons orbit the nucleus
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when did niels bohr live?
1885-1962
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what was bohr’s background?
lived in copenhagen as 2 of 3 kids in an upper middle class family, studied physics at the university of copenhagen and polytechnic institute
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what inspired bohr’s model?
wanted to try to solve the problems with rutherford’s model using quantum model
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what did bohr’s model say?
electrons are found in energy levels or shells and electrons only move by absorbing or emitting energy
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was bohr’s model accepted?
considered radical for a while but now widely used by teachers even though it only works for the lighter elements and violates the Heisenberg uncertainty principle
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when did james chadwick live?
1891-1974
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what was chadwick’s background?
attended manchester university and studied under rutherford and went to study in berlin but was imprisoned in an internment camp for 4 years during WW1 and after release worked in cavendish’s lab
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what inspired chadwick’s model?
interested in the bombardment of particles and determined the mass of each particle was over the mass of a proton
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what did chadwick’s model say?
he found and proved the existence of a neutron
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was chadwick’s model accepted?
yes
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when did erwin schrodinger live?
1887-1961
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what was schrodinger’s background?
lived in vienna, austria and was widely educated, enlisted in WW1 but returned to research after
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what inspired schrodinger’s model?
applied quantum theory
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what did schrodinger’s model say?
theorized that electrons have wavelike behavior and are found in orbitals in the electron cloud
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was schrodinger’s model accepted?
it is the most recent and accurate model
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why did plato reject democritus’ theory?
democritus had based his model on philosophy and did not have scientific proofw
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why did aristotle reject democritus’ theory?
he believed everything was made of earth, water, air, and fire
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why did the roman catholic church reject democritus’ theory?
it is never said in the bible that God created atoms
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what is a corpuscle?
thomson originally called electrons corpuscles
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what is an atom?
An atom is made up of a nucleus of positively charged protons and electrically neutral neutrons, with negatively charged electrons orbiting around it
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what is a cathode ray tube?
a vacuum tube that has two charged plates on either end that when a voltage flows through turns pink
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what is the plum pudding model?
this was thomson’s model that said an atom was a cloud of positive matter with embedded negative particles making the model look like plum pudding
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what was the oil drop experiment?
has atomized oil particles pass through a charged metal plate and then getting radiated and being suspended by voltage
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what was the gold foil experiment?
when alpha particles are fired at a gold sheet within a detecting screen most particles passed through but a few reflected back