CHEMISTRY GLOSSARY

actinium    →   aktinij

Actinium was discovered by André Debierne (France) in 1899. The origin of the name comes from the Greek word aktinos meaning ray. It is heavy, silvery-white, very radioactive metal. Reacts with water. Glows in the dark. Actinium is extremely rare, found in all uranium ores. Usually obtained by treating radium with neutrons in a reactor.

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.

AMU    →   AMU

AMU or atomic mass unit is a unit of mass used to express relative atomic masses. It is equal to 1/12 of the mass of an atom of the isotope carbon-12 and is equal to 1.66 033×10^-27 kg. This unit superseded both the physical and a chemical mass unit based on oxygen-16 and is sometimes called the unified mass unit or the dalton.

becquerel    →   bekerel

Becquerel (Bq) is the SI derived unit, with a special name, for radioactivity, equal to s^-1. It describes a radioactivity of an amount of radionuclide decaying at the rate, on average, of one spontaneous nuclear transition per second. The unit was named after the French scientist Antoine Henri Becquerel (1852-1908) (disintegrations per unit time), equal to s^-1.

argon    →   argon

Argon was discovered by Lord Raleigh and Sir William Ramsay (Scotland) in 1894. The origin of the name comes from the Greek word argos meaning inactive. It is colourless and odourless noble gas. Chemically inert. It is the third most abundant element in the earth’s atmosphere and makes up about 1 %. Argon is continuously released into the air by decay of radioactive potassium-40. Pure form is obtained from fractional distillation of liquid air. Used in lighting products. It is often used in filling incandescent light bulbs. Some is mixed with krypton in fluorescent lamps. Crystals in the semiconductor industry are grown in argon atmospheres.

berkelium    →   berkelij

Berkelium was discovered by Stanley G. Thompson, Albert Ghiorso and Glenn T. Seaborg (USA) in 1949. Named after Berkeley, a city in California, home of the University of California, USA. It is synthetic radioactive metal. Berkelium was made by bombarding americium with alpha particles.

bohrium    →   bohrij

Bohrium was discovered by Peter Armbruster, Gottfried Münzenber and their co-workers at the Heavy Ion Research Laboratory (Gesellschaft für Schwerionenforschung, GSI) in Darmstadt, Germany in 1981. Named in honour of Niels Bohr, the Danish physicist. It is synthetic radioactive metal. Bohrium was produced by bombarding bismuth-204 with chromium-54.

californium    →   kalifornij

Californium was discovered by Stanley G. Thompson, Kenneth Street Jr. and Albert Ghiorso (USA) in 1950. Named after the State and University of California, USA. It is synthetic radioactive metal. Powerful neutron emitter. Californium was made by bombarding curium with helium ions.

beta particle    →   beta-čestica

Beta particle is a charged particle emitted from a radioactive atomic nucleus either natural or manufactured. The energies of beta particles range from 0 MeV to 4 MeV. They carry a single charge; if this is negative, the particle is identical with an electron; if positive, it is a positron.

An unstable atomic nucleus changes into a nucleus of the same mass number but different proton number with the emission of an electron and an antineutrino (or a positron and a neutrino)

carbon    →   ugljik

Carbon has been known since ancient times. The origin of the name comes from the Latin word carbo meaning charcoal. Graphite form of carbon is a black, odourless, slippery solid. Graphite sublimes at 3825 °C. Diamond form is a clear or colored; an extremely hard solid. C60 is Buckminsterfullerine. Carbon black burns readily with oxidants. Carbon is made by burning organic compounds with insufficient oxygen. There are close to ten million known carbon compounds, many thousands of which are vital to organic and life processes. Radiocarbon dating uses the carbon-14 isotope to date old objects.