Isotopes, Radioactivity and Radiation💥
Isotopes are different forms of the same element. e.g. carbon-12, carbon-14. most elements have different isotopes but only some are stable and the rest are radioactive and tend to give out radiation, which is where all radioactivity comes from.
Radioactivity is a totally random process and when it does happen the decayed nucleus will give out either alpha, beta or gamma radiation.
All of the three types of radiation are ionising which means they give or take an electron to turn the atom into an ion. You will have to know all these types in I/GCSE Physics. Alpha pulls an electron out of its orbit. Beta push an electron out of orbit and gamma give the electron energy until it has enough to break free.
Alpha particles:1️⃣
they are made up of two protons and two neutrons, so they are helium nuclei. they are relatively big and heavy and slow moving. they have strong positive charge which is why they can pull out negative electrons. They are strongly ionising so create lots of ions but they don't penetrate far into materials and are stopped quickly. they can be stopped by paper, skin or 5cm of air.
Beta particles:2️⃣
They move quite fast and are quite small. they have a negative cahrge so they repel negative electrons. they are moderately ionising and can penetrate moderately far into materials before being stopped. they can be stopped by thin aluminium. for every beta particle emitted a neutron turns into a proton.
Gamma rays:3️⃣
They are weakly ionising and can penetrate a long way into materials before eventually interacting with an atom. They are an electromagnetic wave. They cannot be stopped, only slowed down by very thick lead.
Nuclear fission:
Nuclear fission is the splitting up of uranium atoms that release a huge amount of energy which is used in nuclear power stations to make electricity.
A slow moving neutron is fired at an isotope of uranium. the neutron is absorbed by the nucleus- this makes the atom unstable and causes it to split. When the atom is split to daughter nuclei are released along with heat energy. the two daughter nuclei are radioactive as they have the "wrong" number of neutrons inside them.
References: https://world-nuclear.org/getmedia/fad063be-d367-4e28-b882-d28a170638d7/pressurized-water-reactor-pwr.png.aspx
Drafted by Catrina (Physics)