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27 Cards in this Set
- Front
- Back
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Define transition metal
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A d block element that forms an ion with an incomplete d sub shell
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Define d block element
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They are found between Group 2 and Group 3, where electrons are filling d orbitals. The d sub shell is the HIGHEST ENERGY sub shell
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Which two elements are not classed as transition metals
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Scandium as it forms only the Sn3+ ion where d orbitals are empty
Zinc as it forms only the Zn2+ ion where d orbitals are full |
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Energy levels when filling orbitals
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4s sub shell has a lower energy than the 3d sub shell, so the 4s orbitals fills first.
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Which two elements have orbitals filled differently?
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Chromium - the 3d and 4s orbitals all contain one electron (Ar 4s1 3d5)
Copper - the 3d orbitals are filled with only one electron in 4s (Ar 4s1 3d10) To reduce electron repulsion a between outer electrons and increase stability |
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Properties of transition metals
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General metal properties (high bp and mp, high densities)
Form compounds with different oxidation states Form coloured compounds Catalyse reactions |
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Colours of compounds
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Transition metals as catalysts
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They provide a surface on which a reaction can take place, the reactants are adsorbed then desorbed
They provide a lower activation energy |
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Important reactions catalysed by transition metals
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The Haber Process - Fe increases rate and lowers temp
The Contact Process - Vanadium oxide (+5) manufacture of H2SO4 Hydrogenation of Alkenes - nickel lowers temp and pressure |
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Precipitation reactions with NaOH: Cu2+
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Cu2+ + 2OH- ---> Cu(OH)2
Pale blue solution - pale blue precipitate |
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Co2+ and NaOH
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Co2+ + 2OH- ---> Co(OH)2
Pink solution - blue precipitate, turning beige in prescience of air |
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Fe2+ and NaOH
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Fe2+ + OH- --> Fe(OH)2
Pale green solution - green precipitate, turning rusty brown on standing due to oxidation |
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Fe3+ + NaOH
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Fe3+ + 3OH- ---> Fe(OH)3
Pale yellow solution ---> rusty brown precipitate |
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Define complex ion
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A transition metal ion bonded to one or more ligands by coordinate bonds
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Define ligand
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A molecule or ion that can donate a pair of electrons with the transition metal ion to form a coordinate bond
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The coordination number
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The total number if coordinate bonds formed between a central metal ion and its ligands
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Common ligands
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They all have one or more lone pairs of electrons in their outer energy level
Water, :OH2 Ammonia, :NH3 Cyanide, :CN- Hydroxide :OH- |
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Define monodentate ligand
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A ligand that donates just one pair of electrons to the central metal ion to form one coordinate bond
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The octahedral shape, picture and bond angle
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Six coordinate bonds, four of the ligands are in the same plane, one is above and one below
Bond angle is 90 |
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Define stereoisomers
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Species with the same structural formula but with a different arrangement of the atoms in space
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Name the two types of stereoisomers
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Cis-trans isomerism
Optical isomerism |
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How can cis-trans occur and a diagram/ example
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When octahedral complexes contain four of one ligand and two of another e.g (Co(NH3)4(Cl2)+ forms a purple cis isomer an green trans
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Cis trans in four coordinate complexes
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They have a square planar shape, and must contain two of one ligand and two of another
E.g NiCl2(NH3)2 |
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Define bidentate ligand
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The ligand can donate two lone pairs of electrons to the central metal ion to form two coordinate bonds
They form octahedral complexes with coordinate number 6 |
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Can bidentate ligands show cis-trans isomerism?
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Yes, e.g (Cr(C2O4)2(H2O)2)-
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What are the requirements for optical isomerism?
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A complex with three molecules or ions of a bidentate ligand
A complex with two molecules or ions of a bidentate ligand and two molecules or ions of a monodentate ligand A complex with one hexadenate ligand |
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What are optical isomers
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Non superimposable mirror images of each other. One if the isomers rotates plane polarised light clockwise and the other anticlockwise
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