Transactinide element
Encyclopedia
In chemistry
, transactinide elements (also, transactinides, or super-heavy elements) are the chemical element
s with atomic number
s greater than those of the actinide
s, the heaviest of which is lawrencium
(103).
Transactinide elements are also transuranic element
s, that is, have an atomic number greater than that of uranium
(92), an actinide. The further distinction of having an atomic number greater than the actinides is significant in several ways:
Transactinides are radioactive
and have only been obtained synthetically in laboratories. None of these elements has ever been collected in a macroscopic sample. Transactinide elements are all named after nuclear physicists and chemists or important locations involved in the synthesis of the elements.
Chemistry Nobelist Glenn T. Seaborg
who first proposed the actinide concept which led to the acceptance of the actinide series also proposed the existence of a transactinide series ranging from element 104 to 121 and a superactinide series approximately spanning elements 122 to 153. The transactinide seaborgium
is named in his honor.
The term transactinide is an adjective, and is not commonly used alone as a noun to refer to the transactinide elements.
IUPAC defines an element to exist if its lifetime is longer than 10−14 seconds which takes for the nucleus to form an electronic cloud.
* The synthesis of these elements has not been officially attested by IUPAC, while in several cases previous syntheses have been confirmed by other institutions or other methods. The names and symbols given are provisional as no names for the elements have been agreed on.
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, transactinide elements (also, transactinides, or super-heavy elements) are the chemical element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
s with atomic number
Atomic number
In chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
s greater than those of the actinide
Actinide
The actinide or actinoid series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium.The actinide series derives its name from the group 3 element actinium...
s, the heaviest of which is lawrencium
Lawrencium
Lawrencium is a radioactive synthetic chemical element with the symbol Lr and atomic number 103. In the periodic table of the elements, it is a period 7 d-block element and the last element of actinide series...
(103).
Transactinide elements are also transuranic element
Transuranium element
In chemistry, transuranium elements are the chemical elements with atomic numbers greater than 92...
s, that is, have an atomic number greater than that of uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
(92), an actinide. The further distinction of having an atomic number greater than the actinides is significant in several ways:
- The transactinide elements all have electrons in the 6d subshell in their ground state (and thus are placed in the d-blockD-blockThe d-block is the portion of the periodic table that contains the element groups 3-12. These groups correspond to the filling of the atomic d-orbital subshell, with electron configurations ranging from s2d1 to s2d10...
). The last actinide, lawrencium, also has one electron in the 6d subshell. - Except for dubniumDubniumThe Soviet team proposed the name nielsbohrium in honor of the Danish nuclear physicist Niels Bohr. The American team proposed that the new element should be named hahnium , in honor of the late German chemist Otto Hahn...
, even the longest-lasting isotopes of transactinide elements have extremely short half-lives, measured in seconds, or smaller units. - The element naming controversyElement naming controversyThe names for the chemical elements 104 to 106 were the subject of a major controversy starting in the 1960s, described by some nuclear chemists as the Transfermium Wars because it concerned the elements following fermium on the periodic table....
involved the first five or six transactinide elements. These elements thus used three-letter systematic namesSystematic element nameA systematic element name is the temporary name and symbol assigned to newly synthesized and not yet synthesized chemical elements. In chemistry, a transuranic element receives a permanent name and symbol only after its synthesis has been confirmed. In some cases, this has been a protracted and...
for many years after their discovery had been confirmed. (Usually the three-letter names are replaced with two-letter names relatively shortly after a discovery has been confirmed.)
Transactinides are radioactive
Radioactive decay
Radioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles . The emission is spontaneous, in that the atom decays without any physical interaction with another particle from outside the atom...
and have only been obtained synthetically in laboratories. None of these elements has ever been collected in a macroscopic sample. Transactinide elements are all named after nuclear physicists and chemists or important locations involved in the synthesis of the elements.
Chemistry Nobelist Glenn T. Seaborg
Glenn T. Seaborg
Glenn Theodore Seaborg was an American scientist who won the 1951 Nobel Prize in Chemistry for "discoveries in the chemistry of the transuranium elements", contributed to the discovery and isolation of ten elements, and developed the actinide concept, which led to the current arrangement of the...
who first proposed the actinide concept which led to the acceptance of the actinide series also proposed the existence of a transactinide series ranging from element 104 to 121 and a superactinide series approximately spanning elements 122 to 153. The transactinide seaborgium
Seaborgium
Seaborgium is a synthetic chemical element with the symbol Sg and atomic number 106.Seaborgium is a synthetic element whose most stable isotope 271Sg has a half-life of 1.9 minutes. A new isotope 269Sg has a potentially slightly longer half-life based on the observation of a single decay...
is named in his honor.
The term transactinide is an adjective, and is not commonly used alone as a noun to refer to the transactinide elements.
IUPAC defines an element to exist if its lifetime is longer than 10−14 seconds which takes for the nucleus to form an electronic cloud.
List of the transactinide elements
- 104 RutherfordiumRutherfordiumRutherfordium is a chemical element with symbol Rf and atomic number 104, named in honor of New Zealand physicist Ernest Rutherford. It is a synthetic element and radioactive; the most stable known isotope, 267Rf, has a half-life of approximately 1.3 hours.In the periodic table of the elements,...
, Rf - 105 DubniumDubniumThe Soviet team proposed the name nielsbohrium in honor of the Danish nuclear physicist Niels Bohr. The American team proposed that the new element should be named hahnium , in honor of the late German chemist Otto Hahn...
, Db - 106 SeaborgiumSeaborgiumSeaborgium is a synthetic chemical element with the symbol Sg and atomic number 106.Seaborgium is a synthetic element whose most stable isotope 271Sg has a half-life of 1.9 minutes. A new isotope 269Sg has a potentially slightly longer half-life based on the observation of a single decay...
, Sg - 107 BohriumBohriumBohrium is a chemical element with the symbol Bh and atomic number 107 and is the heaviest member of group 7 .It is a synthetic element whose most stable known isotope, 270Bh, has a half-life of 61 seconds...
, Bh - 108 HassiumHassiumHassium is a synthetic element with the symbol Hs and atomic number 108. It is the heaviest member of the group 8 elements. The element was first observed in 1984...
, Hs - 109 MeitneriumMeitneriumMeitnerium is a chemical element with the symbol Mt and atomic number 109. It is placed as the heaviest member of group 9 in the periodic table but a sufficiently stable isotope is not known at this time which would allow chemical experiments to confirm its position, unlike its lighter...
, Mt - 110 DarmstadtiumDarmstadtiumDarmstadtium is a chemical element with the symbol Ds and atomic number 110. It is placed as the heaviest member of group 10, but no known isotope is sufficiently stable to allow chemical experiments to confirm its placing in that group...
, Ds - 111 RoentgeniumRoentgeniumRoentgenium is a synthetic radioactive chemical element with the symbol Rg and atomic number 111. It is placed as the heaviest member of the group 11 elements, although a sufficiently stable isotope has not yet been produced in a sufficient amount that would confirm this position as a heavier...
, Rg - 112 Copernicium, Cn
- 113 UnuntriumUnuntriumUnuntrium is the temporary name of a synthetic element with the temporary symbol Uut and atomic number 113.It is placed as the heaviest member of the group 13 elements although a sufficiently stable isotope is not known at this time that would allow chemical experiments to confirm its position...
, Uut* - 114 UnunquadiumUnunquadiumUnunquadium is the temporary name of a radioactive chemical element with the temporary symbol Uuq and atomic number 114. There is no proposed name yet, although flerovium has been discussed in the media.About 80 decays of atoms of...
, Uuq - 115 UnunpentiumUnunpentiumUnunpentium is the temporary name of a synthetic superheavy element in the periodic table that has the temporary symbol Uup and has the atomic number 115....
, Uup* - 116 UnunhexiumUnunhexiumUnunhexium is the temporary name of a synthetic superheavy element with the temporary symbol Uuh and atomic number 116. There is no proposed name yet although moscovium has been discussed in the media.It is placed as the heaviest member of group 16 although a sufficiently stable isotope is...
, Uuh - 117 UnunseptiumUnunseptiumUnunseptium is the temporary name of a superheavy artificial chemical element with temporary symbol Uus and atomic number 117. Six atoms were detected by a joint Russia–US collaboration at Dubna, Moscow Oblast, Russia, in 2009–10...
, Uus* - 118 UnunoctiumUnunoctiumUnunoctium is the temporary IUPAC name for the transactinide element having the atomic number 118 and temporary element symbol Uuo. It is also known as eka-radon or element 118, and on the periodic table of the elements it is a p-block element and the last one of the 7th period. Ununoctium is...
, Uuo*
See also
- Transuranium elementTransuranium elementIn chemistry, transuranium elements are the chemical elements with atomic numbers greater than 92...
- Bose-Einstein condensate (also known as Superatom)
- Island of stabilityIsland of stabilityThe island of stability in nuclear physics describes a set of as-yet undiscovered isotopes of transuranium elements which are theorized to be much more stable than others...