Atoms and radioactivity

What are the 3 subatomic particles?

protons, neutrons, electrons

What subatomic particles are found in the nucleus?

protons and neutrons

What is the charge of an electron?

-1

What is the charge of a proton

+1

What is the charge of a neutron?

0

What is the mass of a proton and neutron?

1.67 x 10^-27 kg (2000x an electron)

What is the mass of an electron?

1

What is the atomic number (Z)

the number of protons in an atom

What is the mass number

Number of protons and neutrons

What are isotopes?

Atoms of the same element with different numbers of neutrons (isotopes have similar chemical properties but different physical properties)

What is the stability of isotopes compared to the original atom

Isotopes are less stable

What is the ionising radiation ?

any radiation that can knock electrons from atoms

What are 4 types of ionising radiation

Alpha radiation

Beta radiation

Gamma rays

Neutron radiation

What happens in alpha decay?

two protons and neutrons lost, atomic mass decreases by 4, atomic number decreases by 2

What is the mass of alpha particles?

4 amu

What is the charge of alpha particles

+2

How is the ionising power different to the penetrating power of alpha particles

- alpha particles have a high ionising power

- they have a low penetrating effect and can be stopped by a piece of paper

What happens in beta minus decay

A neutron turns into a proton and an electron is released

What is the charge of a beta particle

-1

What is the mass of a beta particle

Very light

What is the difference between the ionising power and the penetrating effect of beta radiation

- the ionising effect is lower than alpha radiation, but the penetrating power is more, so a sheet of aluminium needs to be used to stop it

What happens in gamma radiation

high energy emitted after an unstable nuclei emitted an alpha or beta particle

What is the difference between the penetrating power and ionising effect of gamma rays

- gamma rays have a high penetrating power, so a thick brick of concrete or lead is needed to stop it

- they have a weak ionising effect

How do we investigate the penetrating powers of different kinds of radiation

- measure the initial background radiation wit a Geiger-muller tube connected to a counter

- take a source of alpha radiation and set it up at a measured distance from the GM tube

- measure the counts detected in a 5 minute period

- repeat work a sheet of thick paper in front

- then do the experiment with a beta and gamma source

- for the beta source use an aluminum sheet

- for the gamma source use a few centimetres of lead

What is the effect of the atomic and mass number of a nucleus on the emissions of alpha radiation

- the mass number is reduced by 4

- the atomic number is also reduced by 2

What is the effect of the atomic and mass number of a nucleus on the emissions of beta radiation

- the mass number is the same

- the atomic number increases by 1

What is the effect of the atomic and mass number of a nucleus on the emissions of gamma radiation

- there is no change to the atomic number or the mass number

What is the effect of the atomic and mass number of a nucleus on the emissions of neutron radiation

- the atomic number is the same

- the mass number decreases by 1

Differences between alpha and beta radiation

- beta particles are negatively charged while alpha are positively charged

- beta particle has lower mass

- beta is less ionising

- beta has higher speed

- beta particles have larger range

- beta has higher penetrating ability

Which radiation is the fastest

Gamma

Beta

Alpha

What is neutron radiation.

A neutron emitted from an unstable nucleus