Nuclear Reaction

Radioactive -> when nuclei break down spontaneously in some isotopes of some  unstable elements. These isotopes are called radioistopes.

As these nuclei break down, the emit rays and particles called emissions. This break down (radiactive decay) happens on its own accord. Some isotopes can decay very quickly, others can take thousands of years.

There are three different types of emissions: alpha, beta and gamma. All three can knock electrons out of their atoms when they collide, therefore ionising the atoms. This is sometimes referred to as ionising radiation.

Properties of Alpha Emissions:

Relative charge: +2

Relative mass: 4

Nature: 2 protons + 2 neutrons (He nucleus)

Range in air: Few centimetres

Stopped by: Paper

Deflection by electrical field: low

Properties of Beta Emissions:

Relative charge: -1

Relative mass: 0.00055

Nature: electron (produced by nuclear charges)

Range in air: Few metres

Stopped by: Aluminium foil

Deflection by electrical field: high

Properties of Gamma Emissions:

Relative charge: 0

Relative mass: 0

Nature: very high frequency electromagnetic radiation

Range in air: very long

Stopped by: lead sheet

Deflection by electrical field: nil

Nuclear equations:

Alpha decay involves the emission of alpha particles which are helium nuclei. It is common among heavier elements with atomic numbers greater than 83. Alpha decay reduces the mass of these heavy nuclei. The isotope produced by alpha decay will have a mass number four units lower and a nuclear charge two units lower than the original atom.

Beta decay involves the emission of electrons. It is common among lighter elements where the isotopes have a big number of neutrons. During beta decay, the mass number doesn't change but the nuclear charge (proton number) increases by one unit. So,


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Atomic structureEmissions from radioactive substances, Half-life, Calculating and using half-life, uses of radioisotopes in geology, radioactive tracers resources »