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Radioactivity

Radiation - b-particles.

A b-particle (beta particle) is the same as an electron.
It is often called a high energy electron because it is very fast moving.
A b-particle comes from the nucleus of an atom!
It has a charge of  -1 and very little mass (only 1 ÷ 1840 as big as a proton).
Beta Particle
The e shows that the particle is an electron.

It is given a mass number of zero because the mass is very small
compared to a proton or a neutron.
A b-particle has less mass than an a-particle but more mass than a g-ray.

b-particles have more penetrating ability than a-particles
but may be absorbed by a few millimetres of aluminium.
b-particles are less ionising than a-particles but more ionising than g-rays
(see the three types of radiation).

b-particles may be emitted during the decay of either big or small nuclei.
(see examples).

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