Crash Course (Pt 1)
Crash Course (Pt 2)
Define the term radioactivity
Radioactivity is a property of the nucleus of an unstable atom that causes it to spontaneously release radiation.
Compare the features of alpha, beta and gamma radiation
| Alpha | Beta | Gamma | |
|---|---|---|---|
| Image and symbol |  |  |  |
| Nature of Radiation | Matter (2 protons 2 neutrons (helium)) | Electrons | Electromagnetic Radiation |
| Penetrating power (weak/moderate/strong) | Weak | Moderate | Strong |
| Ionising ability (high/med/low/none) | High | Medium | None, but may cause atoms to emit other particles which will then cause ionisation |
| Speed | Slow | Fast | Very fast - speed of light |
| Mass | 4 | Negligible, 1/1838 | 0 |
| Stopped by: | Paper | Plastics (perspex) aluminium | Several metres of water or lead |
| Charge | +2 | -1 | 0 |
| Ionising power refers to how well can it knock out electrons from target atom. | |||
| Penetration power is how far can the ray travel before losing all energy. |
Define the terms isotope and radioisotope
Isotope: An isotope is an atom of a particular element that has the same number of protons but a different number of neutrons.
Radioisotope: Radioisotopes are isotopes where the nucleus is unstable due to the imbalance of protons and neutrons.
(extra:) In some isotopes, the extra neutrons in the nucleus make it harder for the strong nuclear force to keep the nucleus together and the nucleus breaks apart or decays.
When an unstable nucleus breaks up, energy in the form of radiation is released and smaller, more stable elements are formed.
Use the convention for nuclear notation to describe isotopes
E.g. Carbon-13 would be because it has the same amount of protons (6), but one extra neutron, so it has a mass of .
E.g. Uranium-238 would be
Explain nuclear decay using simple balanced decay equations
There are two types of decay we will focus on (although there are three), alpha decay and beta decay.
An alpha particle is . So, when a radioisotope loses an alpha particle, it loses 2 protons (on the bottom) and 2 neutrons (because 2+2=4 on the top). E.g. when it decays and loses an alpha particle, will become .
A beta particle is , so whenever a beta particle is set off, the element will gain an electron, e.g. would become , because 2+1=3 electrons.
Explain the term half-life
- The time required for half of the atoms in a radioactive isotope to decay.
- The groundbreaking 1998 first-person shooter developed by Valve, where players assume the role of theoretical physicist Gordon Freeman as he fights to escape the Black Mesa Research Facility after a scientific experiment triggers a dimensional rift, unleashing hostile aliens from the parallel dimension of Xen.
Plot a decay curve to determine the half-life of a radioisotope
Good luck lol, I was away this lesson
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