That All matter was made of identical lumps called "atomos"
1 of 19
in 1804, What did John Dalton think?
He agreed with Democritus that matter was made of tiny spheres 'atoms' that couldnt be broken up.
2 of 19
What else did John think?
That each element was made up of a different type of atom
3 of 19
100 years later, What did J.J Thomson discover?
Electrons could be removed from atoms. He suggested atoms were spheres of positive charge with tiny negative electrons stuck in them like fruit in a plum pudding
4 of 19
Where did the idea of the "plum pudding model" come from?
From J.J Thompson when he said that atoms had a positive charge with tiny negative electrons stuch in them like fruit in a plum pudding
5 of 19
What happened in 1909 in Rutherford's lab?
Scientists fired a beam of alpha particles at thin gold foil
6 of 19
What is the alpha scattering experiment?
When Scientists fired a beam of alpha particles at gold foil
7 of 19
What did the scientists expect from the aplha scattering experiment?
For the particles to pass staright through the gold sheet or only be slightly defected based on the ideo of the plum pudding model
8 of 19
What were the real results of the alpha scattering experiment?
Most particles went straight through the sheet + some were deflected more than expected + few deflected back the way they had came
9 of 19
Because a few alpha particles were deflected back......
the scientists realised that most of the mass of the atom is concentrated at the centre in a tiny nucleus
10 of 19
The nucleus must have a positive charge because....
it repelled the positive alpha particles
11 of 19
Most of the atom is just an empty space because....
Because nearly all the alpha particles passed straight through
12 of 19
How does the current nuclear model of the atom look like?
Positively charged nucleus sorrounded by a cloud of negative electrons
13 of 19
What did Niels Bohr say about electrons?
Electrons orbit the nucleus at certain distances called energy levels
14 of 19
Niels Bohr's theoretical calculations agreed with what?
It agreed with his experimental data
15 of 19
What did evidence from further experiments change?
The model has a nucleaus made up of group of protons which had a positive charge.
16 of 19
What added up to the overall charge of the nucleus ?
Protons which all had the same positive charge
17 of 19
What did James Chadwick do in 1932?
He proved the existence of the neutron
18 of 19
What do neutrons explain?
The imbalance between the atomic and mass numbers
19 of 19
Other cards in this set
Card 2
Front
in 1804, What did John Dalton think?
Back
He agreed with Democritus that matter was made of tiny spheres 'atoms' that couldnt be broken up.
Card 3
Front
What else did John think?
Back
Card 4
Front
100 years later, What did J.J Thomson discover?
Back
Card 5
Front
Where did the idea of the "plum pudding model" come from?
Comments
No comments have yet been made