radioactivity

Nuclear Model

A model for the atom that has electrons orbiting around a positive nucleus. Discovered by Rutherford.

Isotope

Atoms with the same atomic number but with different numbers of neutrons.

Alpha radiation

The emission of helium nuclei that consist of 2 protons and 2 neutrons (thus having a +2 charge)

Beta radiation

A neutron breaks into a proton (which remains in the nucleus) and releases a fast moving electron.

Gamma

A high energy electromagnetic wave.

Background Radiation

the nuclear radiation that arises naturally from cosmic rays and from radioactive isotopes in the soil and air.

Ionisation

The process by which a neutral atom gains or loses an electron thereby becoming an ion. In human tissue ionisation will cause DNA damage and increase the probability of cell death or mutations.

Half-life

The time taken for half of the atoms in a sample of that radionuclide to decay.

Radioactive decay

A process in which unstable nuclei emit alpha, beta, gamma or neutron radiation. It is random (unpredictable).

Irradiation

the process of exposing an object to radiation. The object does not become radioactive.

Contamination

Occurs if an object has a radioactive material introduced into it. The object becomes radioactive.

what happens in beta plus decay

proton turns into neutron and emmits a positron

what happens in beta minus decay

a neutron turns into a proton and emmits an electron

adding an alpha particle

4/2 a

adding beta minus

0/-1 B/e

adding beta plus

0/1 b

adding neutron emmision as mass decreses but charge stays the same

neutron removed so 1/0

how far can alpha get

5cm or through paper

how far can beta get

1m or through aluminum foil

how far can gama get

1km through lead/concrete