Atomic models Flashcards
(11 cards)
What was the order of the atomic models in history?
Democritus, John Dalton, J.J Thompson (Plum Pudding Model), Ernest Rutherford (Nuclear Model), Niels Bohr, James Chadwick
What was the ‘atomic theory’?
It was the idea that everything is made up of tiny little particles that cannot be broken down any further and are separated by empty space, proposed by Democritus in 500 BC.
What was John Dalton’s suggestion?
In the 1800’s, John Dalton described atoms as solid spheres, suggesting that different types of spheres might make up the different elements.
What did J.J Thompson discover?
He conducted experiments that showed that atoms could not be solid spheres and contained negative particles.
What was J.J Thompson’s model?
He created the plum pudding model in 1897, proposing that the atom was a general ball of positive charge, with a few discrete electrons in it.
What did Ernest Rutherford discover?
He fired positively charged alpha particles at a thin sheet of gold and discovered that some alpha particles were deflected to the side and a small number were even deflected back.
What model did Rutherford suggest?
The Nuclear Model in 1909, proposing a compact nucleus that contained the positive charge of the atom, with the negative charge like a cloud around the nucleus.
What was the flaw in Rutherford’s Nuclear Model?
There was nothing stopping the cloud of negative electrons from rushing into the positive nucleus, meaning that the atom should have collapsed.
What was Niels Bohr’s model?
Bohr suggested that electrons orbited the nucleus similarly to how planets orbit the sun, and that electrons were held in shells, preventing the atom from collapsing.
What was Rutherford’s second discovery?
The nucleus was made up of protons.
What did James Chadwick discover?
The nucleus contained neutrons.