Radioactivity and particles

Question 1

Protons

Answer 1

Charge= +1
Mass= 1

Question 2

Electrons

Answer 2

Charge= -1
Mass= 0

Question 3

Neutron

Answer 3

Charge= 0
Mass = 1

Question 4

Mass and atomic

Answer 4

top number = mass

bottom num = atomic

Question 5

What is the mass number

Answer 5

Number of protons and neutrons

Question 6

What is the atomic number?

Answer 6

Number of protons

Question 7

Plum pudding model

Answer 7

Thompson suggested that atoms were spheres of positive charge with tiny negative electrons stuck in them

Question 8

What was the alpha scattering experiment?

Answer 8

scientists in rutherfords lab tried firing a beam of aplha particles at thin gold foil. Plum pudding theory expected the particles to pass through the gold sheet. Although some did, some were deflected more than they expected. Some were deflected back the same way they had come

Question 9

What did the alpha scattering experiment reveal?

Answer 9

Most of the mass of the atom was concentrated at the centre in a tiny nucleus which has a positive charge

Question 10

lol

Answer 10

number of protons equals number of electrons

Question 11

What are isotopes?

Answer 11

Atoms which have the same number of protons and a different number of neutrons

Question 12

Alpha radiation

Answer 12

Alpha Particles- helium nuclei
2 neutrons and 2 protons
Radiation- particle emitted from nucleus
Don't penetrate far, only can travel a few cm in air and absorbed by a sheet of paper
Strongly ionising

Question 13

Beta particles

Answer 13

A fast moving electron released by nucleus.
No mass and charge of -1
Moderately ionising
Moderately penetrating, absorbed by a sheet of aluminium

Question 14

Why are beta emitters used to test the thickness of sheets of metals?

Answer 14

Because the particles are not immediately absorbed by the material like alpha radiation and do not penetrate as far as gamma rays. Therefore slight variations in thickness affect the amount of radiation passing through the sheet

Question 15

Gamma rays

Answer 15

EM waves
stronly penetrating
weakly ionising
absorbed by thick sheets of lead or metres of concrete

Question 16

Alpha decay

Answer 16

It decreases the charge and mass of the nucleus. loses 2 protons and 2 neutrons

Question 17

Beta decay

Answer 17

It increases the charge of the nucleus. Mass number remains same proton decreases by 1

Question 18

Whats’s a half life?

Answer 18

Time taken for the number of radioactive nuclei in an isotope to halve

Question 19

How to work out half life from a graph

Answer 19

read the initial activity on the y axis. This is activity when time=0
divide by 2
read off time from x axis

Question 20

What is a nuclear fission power plant

Answer 20

A neutron is fired into a uranium-235 nucleus. It becomes unstable and splits into two smaller nuclei and releases 2 or 3 more neutrons

Question 21

How can nuclear fission lead to a chain reaction?

Answer 21

2 more neutrons are released which are reflected by the u235 which undergo fission

Question 22

What is the shield?

Answer 22

concrete absorbs radiation

Question 23

What is the control rod

Answer 23

Boron, absorbs neutrons to slow fission reactants, the higher rectangle

Question 24

What is the fuel rod?

Answer 24

Uranium contains radioactive material for fission, Fatter rectangle

Question 25

What is the moderaotr?

Answer 25

graphite, slows the nutrons down so fission can continue

Question 26

What is nuclear fusion

Answer 26

2 nuclei have to overcome the electrostatic force between them and get close enough for the strong force to hold them together, Converts mass into energy.

Question 27

What is nuclear fission?

Answer 27

type of nuclear reaction that is used to release energy from large and unstable atoms by splitting them into smaller atoms