P1.1 The particle model

Question 1

what are particles?

Answer 1

A tiny bit of matter

Question 2

what did John Dalton suggest?

Answer 2

that all matter is made from atoms, diff elements have diff atoms, all atoms of an element are identical - took many yrs for other scientists to accepts these ideas

Question 3

what did John Dalton believe an atom looked like?

Answer 3

a tiny solid ball - technology of his time didn’t let him investigate in enough detail

Question 4

What did J.J. Thompson investigate?

Answer 4

the rays given out by hot metals, called cathode rays - he wasn’t investigating atoms. He then discovered that cathode rays are made of particles that have less than 1-thousandth of the mass of a hydrogen atom - found electron, must come form inside atom, electron negatively charged

Question 5

what did Ernest Rutherford do?

Answer 5

pointed beams of positively charged particles, called alpha particles at thin gold foil - some particles went straight through, some slightly changed direction, some bounced back.

Question 6

what did Ernest Rutherford suggest?

Answer 6

an atom has a positively charged nucleus, containing most of its mass and outside the nucleus, electrons orbit like planets in a solar system

Question 7

what did Neils Bohr do?

Answer 7

realised orbiting electrons would be attracted to positive nucleus and would rapidly spiral inwards. Bohr showed electrons occupy fixed energy levels, or shells, around the nucleus