nuclear radiation

what is nuclear radiation?

radiation emitted from an unstable atomic nucleus

why do some nuclei emit radiation?

they are unstable and need to become stable

what ate the 3 types of nuclear radiation?

alpha, beta, gamma

what is an alpha particle?

2 protons and 2 neutrons

what charge does an alpha particle have?

+2 (positive)

how far can alpha radiation travel in air?

only a few centimetres

what can stop alpha radiation?

a sheet of paper

is alpha radiation strongly ionising or weekly ionising?

strongly ionising

what is a beta particle?

a fast moving electron

what charge does a beta particle have?

-1 (negative)

how far can beta radiation travel?

further than alpha radiation

what can stop beta radiation?

a thin sheet of aluminium

is beta radiation strongly or weekly ionising?

moderately ionising

what is gamma radiation?

electromagnetic waves released from the nucleus

does gamma radiation have a mass?

no

does gamma radiation have a charge?

no

what can stop gamma radiation?

thick lead or concrete

is gamma radiation strongly ionising or weekly ionising?

weekly ionising

which radiation is the most ionising?

alpha

which radiation is the least ionising?

gamma

which radiation is the most penetrating?

gamma

which radiation is the least penetrating?

alpha

what is radioactive decay?

process where an unstable nucleus emits radiation

is radioactive decay random?

yes

what is an isotope?

atoms of the same element with different number of neutrons

why are some isotopes radioactive?

there nuclei are unstable

what is a half-life?

the time taken for the number of radioactive nuclei to halve

what happens to radioactivity after one half-life?

it halves

what happens after two half-lives?

it halves again (to a quarter of the original amount)