atomic scientists theory timeline Flashcards
what are the 8 names of the scientists in timeline order?
- democritus
- aristotle
- dalton
- thompson
- rutherford
- bohr
- heisenberg & schrodinger
- modern cloud technology
what was the time period of democritus?
400 BC
what did democritus develop?
developed first atomic theory
what does “atomos” mean?
“not to be cut”
what were the 7 things democritus believe about atoms ?
believed that atoms were…
1. solid
2. uniform
3. hard
4. made of the same material
5. different shapes & sizes
6. smallest piece of matter
7. indivisible & indestructible
what shape did democritus say that atoms were in?
spherical shape
what was democritus’ analogy?
legos
what was the time period of aristotle?
300 B.C. to Early 1800s
what 4 things did aristotle say that all matter was made of?
- fire
- water
- earth
- air
what 4 properties did aristotle say that matter had?
- hot
- cold
- dry
- wet
why was aristotle’s ideas so popular?
aristotle had a lot of influence over people so his ideas were easily welcomed
what is the death of chemistry?
when there was no new discoveries made and people believed whatever aristotle said
what was aristotle’s analogy?
“death to the field of chemistry for 2000 years!”
what was the time period for dalton?
1803
what did dalton do since the death of chemistry?
made the first atomic theory since the death of chemistry
what was dalton’s theory?
all atoms of the same element are identical and atoms of different elements are different
what did dalton say about matter?
all matter is made up of atoms
what did dalton say about atoms?
atoms are too small to be seen
what 2 things did dalton find out?
- we might have different elements
- chemical reactions = rearrangement of atoms
what was dalton’s analogy?
billiard ball
what was thompson’s time period?
1897
what was thompson’s famous model called?
“plum pudding”
what are the 3 things that thompson discovered?
- atoms might have subatomic/smaller particles
- electrons have a negative charge
- protons have a positive charge
what is thompson’s analogy?
chocolate chips in a cookie
what was the time period for rutherford?
1908
what 2 things did rutherford discover?
- discovered the nucleus
- electrons are scattered outside the nucleus at a distance
what is rutherford’s theory?
atoms have small, dense, positively-charged center called the nucleus
how did rutherford disprove thompson’s pudding model?
by using positively-charged particles fired at gold foil, he proved atoms are not pudding filled with positively-charged material
what was rutherford’s analogy?
cherry with a pit
what was the time period of bohr?
1913
what did bohr’s model show?
showed what an atom is made of
what was bohr’s theory?
electrons move in definite orbits around the nucleus, like planets around the sun
what 2 things did bohr find out about electrons?
- travel fixed around the nucleus
- energy levels increased for electrons when farther away from nucleus
what was bohr’s analogy?
solar system
what was the time period for heisenberg & schrodinger?
1920s
what 2 things was heisenberg & schrodinger known for?
- equation
- uncertainty principle
what is the uncertainty principle?
cannot know speed and position of a particle at the same time
what was the time period for the modern cloud theory?
20th century
what are the 3 main scientists in the modern cloud theory?
- heisenberg
- schrodinger
- einstein
what did the modern cloud theory uncover about electrons?
electrons do not orbit the nucleus in planet-like orbits, they move at high speeds in an electron cloud around the nucleus
which scientist’s theory did the modern cloud theory disprove?
bohr’s theory about how electrons move at a fixed rate/position around the nucleus
what is the analogy for the modern cloud theory?
cotton ball
