Topic 4

Question 1

John Dalton

Answer 1

Tiny spheres

Question 2

J.J thompson

Answer 2

Particles called electrons could be removed from atoms. Spheres of positive charge. Tiny electrons stuck in them like plum pudding

Question 3

Rutherford

Answer 3

Alpha particle scattering. Thin gold foil
Most particles went straight through. More deflected than expected. Most of mass concentrated at centre of nucleus. Nucleus must have positive charge

Question 4

Bohr

Answer 4

Electrons orbit nucleus at certain distances

Question 5

James Chadwick

Answer 5

Discovery of neutron

Question 6

What’s fission

Answer 6

Spitting large unstable nucleus

Couple neutrons released which if absorbed will cause more fission, chain reaction.

Question 7

What’s nuclear fusion

Answer 7

Joining small nuclei. Collide and fuse to create larger. Heavier nucleus. Some mass of lighter nuclei converted to energy. Released as radiation. Released lots of energy.

Question 8

Alpha

Answer 8

4
2

Atomic number reduces by 2 and mass reduces by 4
Proton positively charges and neutron neutral so charge decreases

Question 9

Beta

Answer 9

0
-1

Neutron turns into proton and releases fast moving electron
Increases positive charge of nucleus

Question 10

Gamma

Answer 10

Don’t change charge or mass of nucleus
Get rid of excess energy
No change to atomic mass or number