CHEMISTRY GLOSSARY

artificial radioactive isotope    →   umjetni radioaktivni izotop

Artificial radioactive isotopes are formed when an atom is bombed with an accelerator or exposing it to slow moving neutrons in a nuclear reactor. In this way isotopes (radionuclides) are obtained which are non-existent in nature because of their unstability and radioactive transition into stable isotopes. Most important radioactive isotopes are:

Radioactive isotope of cobalt is formed when ordinary metal cobalt is bombed with neutrons in a nuclear reactor.

Radioactive isotope of phosphorus is formed when ordinary phosphorus is bombed with deuterons produced in cyclotron.

radioactive isotope of carbon is formed when a nitrogen is bombed with slow moving neutrons in a nuclear reactor. It is mostly used as a radioactive indicator.

isotope    →   izotop

Isotopes are two or more nuclides with the same atomic number Z but different mass number A. The term is sometimes used synonymously with nuclide, but it is preferable to reserve the word nuclide for a species of specific Z and A.

isotone    →   izoton

Isotones are nuclides having the same neutron number N but different atomic number Z.

isotonic solution    →   izotonična otopina

Isotonic solutions are the solutions that have equal osmotic pressure.

isotope proportion    →   izotopni omjer

Isotope proportion is a number of atoms of each isotope in a sample of one element. It uses relative masses of isotopes to calculate a relative mass of one element.

actinides    →   aktinoidi

Actinides (actinons or actinoids) are the fourteen elements from thorium to lawrencium inclusive, which follow actinium in the periodic table. The position of actinium is somewhat equivocal and, although not itself an actinide, it is often included with them for comparative purpose. The series includes the following elements: thorium (Th), protactinium (Pa), uranium (U), neptunium (Np), plutonium (Pu), amercium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), mendelevium (Md), nobelium (No) and lawrencium (Lr). Every known isotope of the actinide elements is radioactive. Traces of Pa, Np and Pu are consequently found, but only Th and U occur naturally to any useful extent.

alpha particle    →   alfa-čestica

Alpha particle is a helium nucleus emitted spontaneously from radioactive elements, both natural and manufactured. Its energy is in range 4-8 MeV and is dissipated in a very short path, i.e. a few centimetres of air or less than 0.005 mm of aluminium. As helium nucleus consists of two protons and two neutrons bound together as a stable entity the loss of an alpha particle involves a decrease in nucleon number of 4 and decrease of 2 in the atomic number, e.g.

A stream of alpha particles is known as an alpha ray or alpha-radiation.

artificial radioactivity    →   umjetna radioaktivnost

Artificial radioactivity is a creation, with the help of an accelerator or in the nuclear reactor, of isotopes (radionuclides) which are found in nature because they are unstable and by radioactive conversion they are converted to stable isotopes.

atom marking    →   markiranje atoma

Atom marking is a process of infusing radioactive isotopes in live organism, with the purpose of revealing a way, diffusion, or a role of certain substance.

carbon dating    →   određivanje starosti radioaktivnim ugljikom

Carbon dating is used to the time passed since a living organism died. It is based on measuring the quantity of isotope of carbon-14 that is contained in all living organisms.