high temperatures. It also forms
complexes with a range of oxidation
states. The element was isolated by
K. K. Klaus in 1844.
A
• Information from the WebElements site
Rutherford, Ernest, Lord (1871–
1937) New Zealand-born British
physicist, who worked under Sir J. J.
*Thomson at Cambridge University
(1895–98). He then took up a professorship at McGill University, Canada,
and collaborated with Frederick
*Soddy in studying radioactivity. In
1899 he discovered *alpha particles
and beta particles, followed by the
discovery of *gamma radiation the
following year. In 1905, with Soddy,
he announced that radioactive
*decay involves a series of transformations. He moved to Manchester
University in 1907 and there, with
Hans Geiger and E. Marsden, devised
the alpha-particle scattering experiment that led in 1911 to the discovery of the atomic nucleus After
moving to Cambridge in 1919 he
achieved the artiÜcial splitting of
light atoms. In 1908 he was awarded
the Nobel Prize for chemistry.
Rutherford backscattering spectrometry (RBS) A technique for
analysing samples of material by
irradiation with a beam of alpha
particles and measurement of the
energies of the alpha particles after
they have been scattered by the
sample. This enables the elements
present and their amounts to be determined because the energy of a
scattered alpha particle depends on
the mass of the nucleus with which
it collides. RBS is used extensively in
medicine and industry.
rutherfordium Symbol Rf. A radioactive *transactinide element; a.n.
104. It was Ürst reported in 1964 at
Dubna, near Moscow, and in 1969 it
was detected by A. Ghiorso and a
team at Berkeley, California. It can
be made by bombarding californium249 nuclei with carbon-12 nuclei.
A
• Information from the WebElements site
Rutherford model The model of
an atom put forward by Ernest
*Rutherford in 1911 on the basis of
experiments on the scattering of
alpha particles. The model consisted
of a very dense positively charged nucleus, with electrons orbiting round
the nucleus. This model presented a
serious difÜculty for the classical
theory of electricity and magnetism,
which predicts that the electron
should spiral into the nucleus in a
fraction of a second, radiating electromagnetic energy while doing so.
This difÜculty led to the development
of the *Bohr theory in 1913 and was
deÜnitively solved by the development of quantum mechanics and its
application to atomic structure in the
mid-1920s.
rutile A mineral form of
titanium(IV) oxide, TiO 2 .
rutile structure A type of ionic
crystal structure in which the anions
have a hexagonal close packed
arrangement with cations in half the
octahedral holes. The coordination
number of the anions is 6 and the coordination number of the cations is
3. compounds with this structures include TiO 2 , MnO 2 , SnO 2 , MgF 2 , and
NiF 2 .
A
• An interactive version of the structure
Ruybal test See scott’s test.
Rydberg constant Symbol R. A
constant that occurs in the formulae
for atomic spectra and is related to
the binding energy between an electron and a nucleon. It is connected to
other constants by the relationship R
Rutherford, Ernest, Lord
468
r
www.AzShimi.ir www.AzShimi.com
complexes with a range of oxidation
states. The element was isolated by
K. K. Klaus in 1844.
A
• Information from the WebElements site
Rutherford, Ernest, Lord (1871–
1937) New Zealand-born British
physicist, who worked under Sir J. J.
*Thomson at Cambridge University
(1895–98). He then took up a professorship at McGill University, Canada,
and collaborated with Frederick
*Soddy in studying radioactivity. In
1899 he discovered *alpha particles
and beta particles, followed by the
discovery of *gamma radiation the
following year. In 1905, with Soddy,
he announced that radioactive
*decay involves a series of transformations. He moved to Manchester
University in 1907 and there, with
Hans Geiger and E. Marsden, devised
the alpha-particle scattering experiment that led in 1911 to the discovery of the atomic nucleus After
moving to Cambridge in 1919 he
achieved the artiÜcial splitting of
light atoms. In 1908 he was awarded
the Nobel Prize for chemistry.
Rutherford backscattering spectrometry (RBS) A technique for
analysing samples of material by
irradiation with a beam of alpha
particles and measurement of the
energies of the alpha particles after
they have been scattered by the
sample. This enables the elements
present and their amounts to be determined because the energy of a
scattered alpha particle depends on
the mass of the nucleus with which
it collides. RBS is used extensively in
medicine and industry.
rutherfordium Symbol Rf. A radioactive *transactinide element; a.n.
104. It was Ürst reported in 1964 at
Dubna, near Moscow, and in 1969 it
was detected by A. Ghiorso and a
team at Berkeley, California. It can
be made by bombarding californium249 nuclei with carbon-12 nuclei.
A
• Information from the WebElements site
Rutherford model The model of
an atom put forward by Ernest
*Rutherford in 1911 on the basis of
experiments on the scattering of
alpha particles. The model consisted
of a very dense positively charged nucleus, with electrons orbiting round
the nucleus. This model presented a
serious difÜculty for the classical
theory of electricity and magnetism,
which predicts that the electron
should spiral into the nucleus in a
fraction of a second, radiating electromagnetic energy while doing so.
This difÜculty led to the development
of the *Bohr theory in 1913 and was
deÜnitively solved by the development of quantum mechanics and its
application to atomic structure in the
mid-1920s.
rutile A mineral form of
titanium(IV) oxide, TiO 2 .
rutile structure A type of ionic
crystal structure in which the anions
have a hexagonal close packed
arrangement with cations in half the
octahedral holes. The coordination
number of the anions is 6 and the coordination number of the cations is
3. compounds with this structures include TiO 2 , MnO 2 , SnO 2 , MgF 2 , and
NiF 2 .
A
• An interactive version of the structure
Ruybal test See scott’s test.
Rydberg constant Symbol R. A
constant that occurs in the formulae
for atomic spectra and is related to
the binding energy between an electron and a nucleon. It is connected to
other constants by the relationship R
Rutherford, Ernest, Lord
468
r
www.AzShimi.ir www.AzShimi.com