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Revision Notes - Transition Metals
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The first transitions series of period 4 are a very similar set of elements
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The difference between transitions metals is the number of d electrons
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This affects their chemistry less than a difference in s or p electrons
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Transition metals are called d block metals, elements which form compounds in
which there is an incomplete subshell of d electrons.
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Scandium (3d10 in compounds) zinc (3d10 in compounds) and copper (3d10 except
in Copper (II) 3d9 compounds) are excluded by this definition.
Physical Properties
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The metallic bond is stronger than in s block metals
There is a measure of stability in a half-full d subshell
d block metals are denser than s block metals and ionisation energies increase
across the period.
Methods of extraction
Transition metals are extracted by reduction of the oxide. Some of the least reactive
elements (Cu, Au and Pt are also found native i.e. combined).
Reduction of the oxide by carbon or carbon monoxide is the usual method of extraction.
Step 1
The ore is concentrated. Sometimes flotation is employed: a stream of water
carries away debris and leaves the denser ore behind.
Step 2
Sulphide ores are then roasted to convert them to oxides
Step 3
Heating with coke reduces the oxide to the metal
Step 4
Carbon is a major impurity in the metal. It is removed by heating the metal in a
stream of air. Further purification may be achieved by electrolysis (e.g., Cu,
Ag and Cr).
Chemical Properties
Features of transition metals include
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Variable oxidation states
Their use as catalysts
Paramagnetism
The formation of Complex ions
The formation of coloured ions
Naming
In the formula of a complex ion, the symbol for the central atom appears first, followed by
the anionic ligands and then by neutral ligands. E.g.
[CoCl2(NH3)4] +
The formula for the complex ion is enclosed in square brackets.
The name of the complex gives the name and oxidation state of the central metal cation,
e.g., cobalt (III), preceded by the name and number of ligands attached to it, e.g.,
hexaaminecobalt (III) ion [Co(NH3)6] 3+
The prefixes Di tri
tetra penta
hexa are used to show the number of ligands.
If several ligands are present, they are listed in alphabetical order, and the prefixes, di, tri,
etc., are not allowed to alter this order, e.g.
[CrCl2(H2O)4 ] +
Tetraaquadichlorochromium (III) ion
If the complex is an anion, the suffix –ate follows the name of the metal, e.g., zincate and
chromate. If the metal has a Latin name, then in the complex anion the Latin name of the
metal is used, followed by the suffix –ate, e.g.
[Fe(CN)6 ] 4Hexacyanoferrate (II)