Unit 2 4:1Development of the Atomic Theory Flashcards
Who is Democritus
The Greek philosopher who came up with the first theory of atoms: suggested that the universe was made of indivisible units called atoms
(did not have evidence for his theory)
What did Dalton add to the atomic theory
All. Atoms of a given element were exactly alike, and atoms of different elements could join to form compounds
(Used experimental evidence)
(Did not fit all observations)
Law of Definite proportions
A chemical compound always contains the same elements in exactly the same proportions by weight or mass (dalton)
How did Thomson discover the electron?
Cathode ray experiment suggested that cathode Rays were made of negatively charged …therefore ELECTRONS
Electron
A subatomic particle that has a negative charge
Who developed the plum- pudding model
Thompson
What is the plum- pudding model
Electrons are spread the light the atom like blueberries in a muffin or chocolate chips in a cookie
What is Rutherford’s atomic model and his discoveries
The mass of the atom was concentrated at the atoms center.
Conducted the gold foil experiment.
Discovered nucleus
Who discovered the nucleus
Rutherford
Nucleus
An atom’s central region which is made up of protons and neutrons
Who came up with the first theory of atoms?
Democritus
