Isotopes Are Atoms That Have

Isotopes are atoms that have the same number of electrons and protons, but they have different numbers of neutrons, therefore a differing mass amount as well. One element can have more than one isotope. For example Carbon-14 is an isotope of a Carbon atom. It contains 6 protons, 6 electrons, and 8 neutrons. A normal carbon atom contains 6 protons, 6 electrons, and 6 neutrons. When you get bigger elements, differing amounts of neutrons result in it being an unstable atom.

How isotopes are similar and how they are different:

Isotopes of the same element are similar in that they have the same; number of protons and electrons, atomic number, and chemical properties. However isotopes differ from each other as the have a different; number of neutrons, and mass number.

What a radioisotope is and how is differs structurally from stable isotopes:

Radioisotopes are radioactive isotopes. Their nuclei are unstable and give of energy called radiation in the form of alpha, beta, and gamma rays. Every element has at least one radioisotopes, for example hydrogen has three isotopes, only hydrogen-3 (tritium) is radioactive.

Radioisotopes differ from normal isotopes as they are always unstable, normal isotopes can be unstable but they also are not. Radioisotopes contain high levels of nuclear energy and emit this energy in the form of nuclear radiation, compared with normal isotopes which contain no radioactivity.

Alpha, gamma and beta radiation and their relevance to radioisotopes:

Alpha radiation is the least penetrating out of alpha, beta and gamma. It goes no more than a few centimetres in the air, and on goes through at a maximum of a couple of sheets of paper. Alpha radiation is made of helium nuclei. Beta radiation penetrates aluminium and wood (thickness of 1cm). It normally goes about metre in the air. Beta radiation is made up of high-speed electrons. Gamma rays are the strongest form of radiation. Gamma rays are nuclear radiation, this is what makes them so dangerous. Gamma rays are pure energy and radiation, only dense matter can deflect it such as lead (2-3cm thick) or a concrete block. Gamma rays are made up of electromagnetic radiation. Radiation is related to radioisotopes as radioisotopes are basically just radioactive isotopes.

What an isotope’s half-life is and what occurs during radioactive decay:

The half-life of an isotope is the time it takes for half atoms radioactive material to disintegrate. The half-life of any atom can vary from seconds to billions of years. In radioactive decay the element starts off as a parent nuclei (the original nucleus) and ends up being a daughter nuclei (the remaining nucleus) after the decay has occurred. It uses a process called transmutation, which is the process of one element changing into another. After either alpha or beta decay has occurred the daughter nucleus is often left in an excited state. The excess energy given up by the nucleus is emitted in gamma radiation.

SECTION 2 – Specific use of radioisotopes researched:

The use of radioisotopes in food and agriculture:

Beta-emitting radioisotopes are used to see the effect that fertilisers have on plants. The radioisotope is injected to the soil around the plant before being tracked by a detector to the path that it takes. This information helps you to understand how particular plants use fertilisers, this therefore helps to identify which fertiliser is most appropriate to use. Some fertilisers have isotopes in them so you can track how much they absorb, nitrogen-15 or phosphorus-32 are the two commonly used isotopes.

Radioisotopes are also used to help control insects. The radiation is used to sterilise the male insects before they hatch. They are released into an affected area and so when they mate with a female the produce no offspring, therefore reducing the amount of insects in the area. This process is called the Sterile Insect Technique (SIT). The SIT is environmentally-friendly, and has been proven effective after normal pesticides were ineffective. The most common radioisotopes used in SIT is Cobalt-60 and Caesium-137.

Irradiation is used to preserve food as is kills the bacteria that cause the food to spoil. Irradiation is a process that uses gamma rays from a source called cobalt-60. Irradiation is alright to use on food as it does not become radioactive. Irradiation is commonly used for astronauts as their food is preserved by irradiation. Unfortunately the radiation may kill vitamins in the food and also may produce unwanted chemicals.

Are the radioisotopes used naturally occurring or synthetic?

The radioisotope Cobalt-60 is not naturally occurring, it is manmade. Caesium-137 is a fission product, its half-life is too short for it to continue from natural fission sources, and therefore on earth is a synthetically created isotope only. Synthetic isotopes are created when an atom is bombarded with an accelerator, or is exposed to slow moving neutrons in a nuclear reactor. These processes make an unstable atom stable, however these now stable atoms are not naturally occurring.

Nuclear chemical equations that show radioactive decay:

The radioactive decay chemical equation for Cobalt-60 is

27Co^60 → 28Ni^60 + -1e^0

Cobalt-60 is a beta radioactive decayer, this means that it gives off beta radiation. It would also give off gamma radiation as gamma rays do not have any charge.

The radioactive decay chemical equation for Caesium-137 is

55Cs^137 → 56Ba^137 + -1e^0

Caesium-137 is a beta radioactive decayer, therefore gives off beta radiation and also gamma radiation (neutral charge).

*The number in front of the symbol is its atomic number, the number following the symbol and preceded by ^ represents the atomic mass.

How people and the environment are protected when the isotopes are used:

Most of the radioisotopes used in food and agriculture are used in small amounts and are safe. The radioisotopes used in the food industry would obviously be safe because other wise why would we consume it. However when the application is being done, the right safety measures are used. It is very much like x-raying.