Recent Discoveries of Elements (1 Viewer)
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- Start date
someth1ng
Retired Nov '14
It can be anything from like, the 1950s or so afaik but there isn't anything specific.
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Hi,
It is me Omed.
This is a very simple part of the syllabus.
The manufacture of synthetic elements began with Glenn T. Seaborg and his
team at Lawrence Berkeley National Laboratory (LBNL) in the late 1940s. He
succeeded in synthesising neptunium and plutonium from uranium. Between
1944 and 1953 this team established the existence of americium, curium,
berkelium, californium, einsteinium,
fermium, mendelevium and nobelium. Element 106 (seaborgium, Sg) has since
been named in honour of Glenn Seaborg. The production of even heavier
synthetic elements continues to the present time.
Theories of nuclear stability had predicted that super-heavy nuclei with atomic
numbers around 114 would be more stable than other superheavy elements. In
1999 a research team at Dubna in Russia announced the discovery of element
114. Its half-life was 30 seconds. This is considerably longer than the half-lives
of other superheavy nuclei, which are measured in milliseconds. The first isotope
of element 114 was created by colliding a calcium-48 ion into a plutonium-244
target using a heavy ion accelerator. Calcium-48 is a rare isotope of calcium,
and plutonium is a highly toxic, radioactive metal. A lighter isotope of element-
114 was also created by bombarding Pu-242 with Ca-48 ions. Its half-life was 5
seconds.
Uuq-292 rapidly lost 4 neutrons, and the resulting isotope decayed by alpha
emission to elements of lower atomic number. The first three steps of the decay
chain are shown below.
In 1999, the LBNL team in California claimed to have produced three atoms of
element 118 (Uuo) by bombarding lead targets with an intense beam of highenergy
krypton ions in a synchrotron. Element 116 (Uuh) was identified as a
decay product. In 2000 the LBNL team announced the discovery of element 116
produced by bombarding curium-248 with calcium-48 ions. In 2001, the Berkeley
team withdrew its claim to have discovered elements 118 and 116 in its 1999
experiments, as they could not repeat their discovery in experiments conducted
in 2000. As well, other researchers in Japan and Germany could not reproduce
their work. In July 2002, Victor Ninov, one of the fifteen LBNL researchers was
accused of scientific fraud and misconduct over the analysis of these
experiments, and was dismissed. The group’s director admitted that sufficient
checks on the data and its interpretation were not performed in the rush to
announce the discovery. The discovery of element 116 by another independent
research group in 2001 may be given priority credit by IUPAC.
It is me Omed.
This is a very simple part of the syllabus.
The manufacture of synthetic elements began with Glenn T. Seaborg and his
team at Lawrence Berkeley National Laboratory (LBNL) in the late 1940s. He
succeeded in synthesising neptunium and plutonium from uranium. Between
1944 and 1953 this team established the existence of americium, curium,
berkelium, californium, einsteinium,
fermium, mendelevium and nobelium. Element 106 (seaborgium, Sg) has since
been named in honour of Glenn Seaborg. The production of even heavier
synthetic elements continues to the present time.
Theories of nuclear stability had predicted that super-heavy nuclei with atomic
numbers around 114 would be more stable than other superheavy elements. In
1999 a research team at Dubna in Russia announced the discovery of element
114. Its half-life was 30 seconds. This is considerably longer than the half-lives
of other superheavy nuclei, which are measured in milliseconds. The first isotope
of element 114 was created by colliding a calcium-48 ion into a plutonium-244
target using a heavy ion accelerator. Calcium-48 is a rare isotope of calcium,
and plutonium is a highly toxic, radioactive metal. A lighter isotope of element-
114 was also created by bombarding Pu-242 with Ca-48 ions. Its half-life was 5
seconds.
Uuq-292 rapidly lost 4 neutrons, and the resulting isotope decayed by alpha
emission to elements of lower atomic number. The first three steps of the decay
chain are shown below.
In 1999, the LBNL team in California claimed to have produced three atoms of
element 118 (Uuo) by bombarding lead targets with an intense beam of highenergy
krypton ions in a synchrotron. Element 116 (Uuh) was identified as a
decay product. In 2000 the LBNL team announced the discovery of element 116
produced by bombarding curium-248 with calcium-48 ions. In 2001, the Berkeley
team withdrew its claim to have discovered elements 118 and 116 in its 1999
experiments, as they could not repeat their discovery in experiments conducted
in 2000. As well, other researchers in Japan and Germany could not reproduce
their work. In July 2002, Victor Ninov, one of the fifteen LBNL researchers was
accused of scientific fraud and misconduct over the analysis of these
experiments, and was dismissed. The group’s director admitted that sufficient
checks on the data and its interpretation were not performed in the rush to
announce the discovery. The discovery of element 116 by another independent
research group in 2001 may be given priority credit by IUPAC.
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