Developing The Model Of The Atom

Question 1

What did John Dalton think

Answer 1

Matter was made up tiny spheres that couldn’t be broken up

Each element was made up of a different type of atom

Question 2

What did J J Thompson discover 100 years later

Answer 2

Particles called electrons that could be removed from atoms

Plum pudding model: that atoms were spheres of positive charge with tiny negative electrons in them

Question 3

What did Rutherford discover after?

Answer 3

Alpha scattering experiment: they expected the particles to pass straight theory or slightly deflected but some were deflected

Question 4

What did they gather from the alpha scattering experiment

Answer 4

That most of the mass of the atom must be concentrated at the centre in a tiny nucleus, this nucleus must also have a positive charge, since it repelled the positive alpha particles
And that most of the atom is empty space

Question 5

What did Bohr come up with

Answer 5

Electrons orbiting the nucleus so so at certain distances called energy Keble

Question 6

What did Chadwick prove

Answer 6

Existence of neutron, which explained the imbalance between the atomic and mass numbers

Question 7

Describe the current model of the atom

Answer 7

The centre of an atom is a tiny, positively charged nucleus
Made up protons and neutrons and is the source of most of the atoms mass
Most of the atom is empty space
Electrons orbit the nucleus at set energy levels