ASPC Exam 6

When did Democritus live?

around 460 BC

What was Democritus’ background?

lived in Abdera, Greece but not much known about his early life

what inspired Democritus’ model?

Parmenides’ challenge saying that all matter is in a state of not being or being

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

was Democritus’ model accepted?

no

when did John Dalton live?

1766-1844

what was Dalton’s background?

English chemist and physicist who previously studied meteorology in manchester

what inspired Dalton’s model?

he set out to scientifically prove Democritus’ model

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

was Dalton’s model accepted?

it was a start but did not talk much about the atoms themselves

when did Lord Kelvin live?

1824-1907

what was Lord Kelvin’s background?

lived in Belfast, Ireland, originally named William Thomson, studied as a mathematician, physicist, and engineer

what inspired Lord Kelvin’s model?

the movement of smoke rings like a vortex and sailor knots

what did Lord Kelvin’s model show?

atoms twist and turn like knots

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

when did J.J. Thomson live?

1856-1940

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

what inspired Thomson’s model?

his cathode ray experiment finding corpuscles or electrons and plum pudding

what did Thomson’s model show?

atoms contained negative particles floating within a soup of diffuse positive charge

was Thomson’s model accepted?

his model was soon found to have many problems including no nucleus

when did Robert Millikan live?

1868-1953

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

what inspired Millikan’s model?

his water and oil drop experiments

what does Millikan’s model show?

concrete proof of electron’s negative charge and the amount of charge in an electron

was Millikan’s model accepted?

yes because he had concrete proof

when did Ernest Rutherford live?

1871-1937

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

what inspired rutherford’s model?

his gold foil experiment

what did rutherford’s model show?

determined the presence of the nucleus

was rutherford’s model accepted?

yes except no reason for why electrons orbit the nucleus

when did niels bohr live?

1885-1962

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

what inspired bohr’s model?

wanted to try to solve the problems with rutherford’s model using quantum model

what did bohr’s model say?

electrons are found in energy levels or shells and electrons only move by absorbing or emitting energy

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

when did james chadwick live?

1891-1974

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

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

what did chadwick’s model say?

he found and proved the existence of a neutron

was chadwick’s model accepted?

yes

when did erwin schrodinger live?

1887-1961

what was schrodinger’s background?

lived in vienna, austria and was widely educated, enlisted in WW1 but returned to research after

what inspired schrodinger’s model?

applied quantum theory

what did schrodinger’s model say?

theorized that electrons have wavelike behavior and are found in orbitals in the electron cloud

was schrodinger’s model accepted?

it is the most recent and accurate model

why did plato reject democritus’ theory?

democritus had based his model on philosophy and did not have scientific proofw

why did aristotle reject democritus’ theory?

he believed everything was made of earth, water, air, and fire

why did the roman catholic church reject democritus’ theory?

it is never said in the bible that God created atoms

what is a corpuscle?

thomson originally called electrons corpuscles

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

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

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

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

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

what order did the 9 atomic models occur?

1. democritus

2. dalton

3. lord kelvin

4. thomson

5. millikan

6. rutherford

7. bohr

8. chadwick

9. schrodinger