9-24-15 Flashcards
believed there was a limit on how small matter could be divided
democritus
said there was no limit to how many times matter could be divided
aristotle
believed in the four elements
aristotle
indivisible particles
Democritus
“atomos”
Democritus
solid spheres
dalton
an atom is a tiny solid sphere
with a predictable mass for a given element
dalton
ratio of elements combine is always the same
dalton
agreed with four elements
Democritus
2000 years ago (400 B.C)
Democritus
400 B.C (2000 years ago)
Aristotle
1803
Dalton
jellybeans in a jar
Dalton
all elements are made of atoms
Dalton
compounds are multiple elements
Dalton
solid sphere model
Dalton
indivisible
no smaller than one atom
Dalton
ratios are the same in compounds
Dalton
masses of elements are the same
Dalton
1897
Thomson
seeds in a watermelon
Thomson
discovered electron
Thomson
electrons are negative
Thomson
atoms = plum pudding
Thomson
used electricity to attract and repel a beam of glowing gas
Thomson
1899
Rutherford
marble in a stadium
Rutherford
discovered the nucleus
Rutherford
gold foil experiment
Rutherford
found a positive charge in the nucleus
Rutherford
1913
Bohr
solar system
Bohr
organized electrons into predictable levels
Bohr
electrons can move from one level to another (quantum leap)
Bohr
electrons move down, light is released
Bohr
1926
Modern Atomic Theory
rolling dice
MAT
electron cloud model
MAT
can only predict where electrons can be found
MAT
area where electron is likely to be found
orbital (MAT)
