Group 9 element
Encyclopedia
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| 4 Period 4 element A period 4 element is one of the chemical elements in the fourth row of the periodic table of the elements. The periodic table is laid out in rows to illustrate recurring trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour... |
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| 5 Period 5 element A period 5 element is one of the chemical elements in the fifth row of the periodic table of the elements. The periodic table is laid out in rows to illustrate recurring trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour... |
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| 6 Period 6 element A period 6 element is one of the chemical elements in the sixth row of the periodic table of the elements, including the lanthanides... |
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| 7 Period 7 element A period 7 element is one of the chemical elements in the seventh row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical... |
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In modern IUPAC nomenclature, Group 9 of the periodic table
Periodic table
The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...
contains the elements
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...
cobalt
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....
(Co), rhodium
Rhodium
Rhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed...
(Rh), iridium
Iridium
Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...
(Ir), and meitnerium
Meitnerium
Meitnerium 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). These are all d-block
D-block
The 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...
transition metal
Transition metal
The term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some...
s. All known isotopes of Mt are radioactive with short half-lives, and it is not known to occur in nature; only minute quantities have been synthesized in laboratories.
Like other groups, the members of this family show patterns in its electron configuration
Electron configuration
In atomic physics and quantum chemistry, electron configuration is the arrangement of electrons of an atom, a molecule, or other physical structure...
, especially the outermost shells resulting in trends in chemical behavior, though rhodium curiously does not follow the pattern:
Chemistry
| Z 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... | 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... | No. of electrons/shell Electron shell An electron shell may be thought of as an orbit followed by electrons around an atom's nucleus. The closest shell to the nucleus is called the "1 shell" , followed by the "2 shell" , then the "3 shell" , and so on further and further from the nucleus. The shell letters K,L,M,..... |
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| 26 | cobalt | 2, 8, 15, 2 |
| 44 | rhodium | 2, 8, 18, 16, 1 |
| 76 | iridium | 2, 8, 18, 32, 15, 2 |
| 108 | meitnerium | 2, 8, 18, 32, 32, 15, 2 |
Meitnerium has not been isolated in pure form, and its properties have not been conclusively observed; only cobalt, rhodium, and iridium have had their properties experimentally confirmed. All three elements are typical silvery-white transition metals, hard, and have high melting and boiling points.
History
Cobalt has been discovered in Egyptian and Persian artifacts from before the 2nd millenium BCE. Rhodium was discovered in 1803 when William Hyde WollastonWilliam Hyde Wollaston
William Hyde Wollaston FRS was an English chemist and physicist who is famous for discovering two chemical elements and for developing a way to process platinum ore.-Biography:...
dissolved platinum ore in aqua regia
Aqua regia
Aqua regia or aqua regis is a highly corrosive mixture of acids, fuming yellow or red solution, also called nitro-hydrochloric acid. The mixture is formed by freshly mixing concentrated nitric acid and hydrochloric acid, usually in a volume ratio of 1:3, respectively...
, then neutralized the acid with sodium hydroxide. Wollaston then added ammonium chloride, and dissolved all metals except rhodium and palladium
Palladium
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...
with the nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
in the aqua regia. Iridium was discovered in a very similar way in 1804 by Smithson Tennant
Smithson Tennant
Smithson Tennant FRS was an English chemist.Tennant is best known for his discovery of the elements iridium and osmium, which he found in the residues from the solution of platinum ores in 1803. He also contributed to the proof of the identity of diamond and charcoal. The mineral tennantite is...
. Meitnerium was discovered in 1982 by bombarding bismuth-209
Bismuth-209
Bismuth-209 is the isotope of bismuth with the longest half-life. It has 83 protons and 126 neutrons, and an atomic mass of 208.9803987 u. All primordial bismuth is of this isotope...
with iron-58.
Occurrence
All group 9 elements are relatively rare in the earth's crust, with the most abundant, cobalt, only accounting for 0.0029% of the EarthEarth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's crust. Rhodium and Iridium are two of the rarest naturally occurring elements in the earth, only found in platinum ores. Meitnerium has only been produced in nuclear reactors and has never been observed in nature nor isolated in pure form.
Biological occurrence
Cobalt is an essential trace nutrient to all animals, found in vitamin B-12. Rhodium, Iridium, and Meitnerium have no known biological roles.Applications
- Alloys with other metals, primarily to add corrosion and wear resistance
- Industrial Catalysts
- Superalloys
- Electrical Components
See also
- Platinum groupPlatinum groupThe platinum group metals is a term used sometimes to collectively refer to six metallic elements clustered together in the periodic table.These elements are all transition metals, lying in the d-block .The six...
>Explanation of right side periodic table slice: Transition metal Transition metalThe term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some...
satomic number in black are solids solid borders are older than the Earth EarthEarth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
(Primordial elements)dashed borders have no isotopes older than the earth