Ionising radiations
Normally, atoms are neutral. They have the same number of protonSubatomic particle with a positive charge and a relative mass of 1. The relative charge of a proton is +1. in the nucleusThe central part of an atom. It contains protons and neutrons, and has most of the mass of the atom. The plural of nucleus is nuclei. as they have electronSubatomic particle, with a negative charge and a negligible mass relative to protons and neutrons. orbiting in the energy levelsSpecific amounts of energy that electrons have when they orbit a nucleus is a particular shell. Electrons that gain energy may move to a higher energy level (a shell further from the nucleus). Electrons that lose energy may move to a lower energy level (a shell closer to the nucleus). around the nucleus.
Atoms can, however, lose or gain electrons due to collisions or other interactions, often with nuclear radiation. When they do, they form charged particles called ionElectrically charged particle, formed when an atom or molecule gains or loses electrons.:
- if the atom loses one or more electrons, it becomes a positively-charged ion
- if the atom gains one or more electrons, it becomes a negatively-charged ion
radioactiveWhen unstable atoms give off particles that can be harmful to humans. materials are hazardous. nuclear radiationParticles or waves given out by the nucleus of an unstable atom. Alpha particles, beta particles and gamma waves are the three most common types of nuclear radiation. can ioniseTo ionise is to convert an uncharged atom or molecule into a charged particle by adding or removing electrons. chemicals within a body, which changes the way the cells behave. It can also deposit large amounts of energy into the body, which can damage or destroy cells completely. Ultraviolet, x-rays, alpha, beta and gamma radiations are all examples of ionising radiations. Molecules in cells can be altered as well as the DNA.
Some of the effects that radiationEnergy carried by particles from a radioactive substance, or spreading out from a source. has on a human body are shown below.
| Eyes | High doses can cause cataracts. |
| Thyroid | Radioactive iodine can build up and cause cancer, particularly during growth. |
| Lungs | Breathing in radioisotopes can damage DNA. |
| Stomach | Radioactive isotopes can sit in the stomach and irradiate for a long time. |
| Reproductive organs | High doses can cause sterility or mutations. |
| Skin | Radiation can burn skin or cause cancer. |
| Bone marrow | Radiation can cause leukaemia and other diseases of the blood. |
| Eyes |
|---|
| High doses can cause cataracts. |
| Thyroid |
|---|
| Radioactive iodine can build up and cause cancer, particularly during growth. |
| Lungs |
|---|
| Breathing in radioisotopes can damage DNA. |
| Stomach |
|---|
| Radioactive isotopes can sit in the stomach and irradiate for a long time. |
| Reproductive organs |
|---|
| High doses can cause sterility or mutations. |
| Skin |
|---|
| Radiation can burn skin or cause cancer. |
| Bone marrow |
|---|
| Radiation can cause leukaemia and other diseases of the blood. |