CHEMISTRY GLOSSARY

kilogram    →   kilogram

Kilogram (kg) is the SI base unit of mass; it is equal to the mass of the international prototype of the kilogram.

The prototype of the standard is a cylinder of platinum-iridium alloy (90:10), 39 mm in diameter and 39 mm high. Prototype of the kilogram kept by the Bureau International des Poids et Mesures (International Bureau of Weights and Measures) at Sèevres, near Paris.

nucleon    →   nukleon

Nucleon is a collective term for the proton and neutron.

nuclide    →   nuklid

Nuclide is a species of atoms in which each atom has identical atomic number Z and identical mass number A. For example, a carbon-14 (C-14 or ¹⁴C) nuclide is the nucleus of a carbon atom, which has six protons and eight neutrons.

oxonium ion    →   oksonijev ion

Oxonuim ion (H₃O⁺) is formed when a molecule of water binds with a proton.

subatomic particles    →   subatomske čestice

Subatomic particles are the constituent parts of the atom, such as the electron, proton, neutron, etc.

trituim    →   tricij

Tritium (heavy hydroegn) is a radioisotope of hydrogen with two neutrons and one proton in its nucleus.

lanthanides    →   lantanoidi

Lanthanides (lanthanons, lanthanoids or rare-earth elements) are a series of fourteen elements in the periodic table, generally considered to range in proton number from cerium to lutetium inclusive. It was convenient to divide these elements into the cerium group or light earth: cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu); and the yttrium group or heavy earths: gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) i lutetium (Lu). The position of lanthanum is somewhat equivocal and, although not itself a lanthanide, it is often included with them for comparative purpose. The lanthanides are sometimes simply called the rare earths. Apart from unstable Pm, the lanthanides are actually not rare. Cerium is the 26. most abundant of all elements, 5 times as abundant as Pb. All are silvery very reactive metals.

protactinium    →   protaktinij

Protactinium was discovered by Otto Hahn (Germany) and Lise Meitner (Austria) in 1917. The origin of the name comes from the Greek word protos meaning first. It is very rare, silvery-white, extremely radioactive metal. Resists alkalis; reacts with oxygen and acids. Attacked by steam. Highly radiotoxic. Protactinium is extremely toxic and must be handled with great care. Protactinium does not occur in nature. Found among fission products of uranium, thorium and plutonium.

spin    →   spin

Spin is the intrinsic angular momentum of an elementary particle, or system of particles such as nucleus, that is also responsible for the magnetic moment; or, a particle or nucleus possessing such a spin. The spins of nuclei have characteristic fixed values. Pairs of neutrons and protons align to cancel out their spins, so that nuclei with an odd number of neutrons and/or protons will have a net non-zero rotational component characterized by a non-zero quantum nuclear spin number.

Stern-Gerlach experiment: a beam of silver atoms is split into two beams when it traverses a nonuniform magnetic field. Atoms with spin quantum number m_s=+1/2 follow one trajectory, and those with m_s=+1/2 follow another.

Chitosan    →   Kitozan

Chitosan is a linear polysaccharide composed of randomly distributed N-acetyl D-glucosamine and D-glucosamine units. It can be easily derived from partial deacetylation of natural polymer chitin. At a minimum deacetylization level of 60 % (amount of free amino groups in the polymer) it is considered to be chitosan. Thanks to the amino groups of D-glucosamine, chitosan can be protonated and turned into polycation, which is one of the sources of unique properties of chitosan as biopolymer, like aqueous solubility, antibacterial properties, biodegradability with non-toxic residues and biocompatibility.