Development Of The Atomic Model Flashcards
Who thought that all matter was made up of identical lumps called atomos?
Democritus ( a Greek guy)
When did Democritus theorise atomos?
5th century BC
What did John dalton do and when?
He said that each element had a different type of atom, 1804
When were electrons discovered and by who?
1897, J.J. Thompson
What theory did J.J. Thomson suggest?
The plum pudding model
What was the plum pudding model?
A theory that all atoms were a sphere of positive charge with electrons inside it creating an overall neutral charged sphere
What was the alpha scattering experiment?
Scientists firing a beam of alpha particles at thin gold foil and recording their path of deflection.
What was John daltons theory called?
The bowling ball model
What was the bowling ball model?
The theory that all matter was made up of tiny invisible spheres
What were the results of the alpha scattering experiment?
99% of alpha particles went straight through
Some were deflected (came close with +charge)
Some bounced back ( hit something with mass)
Who did the alpha scattering experiment and when?
Rutherford 1908-1913
What was the model defined by the alpha scattering experiment?
The first nuclear model with a central nucleas that was +charged and carried most of the mass
Electrons orbited the nucleas
What did Bohr discover in 1913?
That electrons move around the nucleas in energy levels (or shells) the order of the energy levels was 2,8,8
What happened in 1932?
James Chadwick discovered neutrons
