Isotopes and Nuclear Radiation

What is an Isotope?

A different form of the same element, with the same number of protons but different number of neutrons.

Radioactive decay

atoms usually have one to two stable isotopes. the other unstable isotopes tend to decay into other elements and give radiation as they become more stable. This is called radioactive decay.

Radioactive substances

They split out one or more types of ionising radiation from they nucleus. They can also release neutrons when they decay,as they rebalance their atomic mass.

Ionising radiation

Radiation that knocks off electrons of atoms, creating positive ions. The ionising power of a radiation source is how easily it can do this.

Alpha radiation

Alpha radiation is when an Alpha particle is emitted from the nucleus. An Alpha particle is two neutrons and two protons (like helium nucleus).

Alpha particles

• They don’t penetrate very far into materials and are stopped quickly - they can only travel a few cm in air and are absorbed by a sheet of paper.

• Because of their size, they are strong ionising

Beta radiation

A fast-moving electron released by the nucleus. Beta particles have virtually no mass and a charge of -1.

Beta particle

• They are moderately ionising.

• They penetrate moderately far into materials before colliding and have a range in air of a few metres.

• they are absorbed by a sheet of aluminium (around 5mm)

• For every beta particle emitted, a neutron in the nucleus has turned into a proton.

Gamma Rays

Ways of electromagnetic radiation released by the nucleus.

Gamma particles

• They penetrate far into meterial without being stopped and will travel a long distance through air.

• This means they are weakly ionising because they tend to pass through rather than collide with atoms. eventually they hit somtehing and do damage

• They can be absorbed by thick sheets of lead or metres of concrete.

What is Alpha Radiation used in?

Smoke detectors - It ionisies air particles causing a current to flow. If there is smoke in the air, it binds to the ions - meaning the current stops and the alarm sounds.