Question | Answer |
Properties of TM | coloured compounds
formation of complexes
variable oxidation states |
Ligand | atom/ion with lone pair of eletrons that forms a co ordinate bond to the metal |
Complex | metal ions with ligands co ordinately bonded to it |
Co ordination number | number of co ordination bonds from ligand(s) to metal ion(s) |
Unidentate ligand | forms one co ordinate bond |
Bidentate ligand | forms two co ordinate bonds |
Multidentate ligand | forms several co ordinate bonds |
Why do the transition metals make good catalysts? | Change oxidation state
Good surface area for adsorption
Transfer electrons to speed up reaction |
Ni | margarine production, hydrogenation
lower temperature and pressure |
V2O5 | produce SO3 in the contact processes required to make sulphuric acid |
Fe | harbor process
increase rate of reaction
decrease temperature |
Pt/Pd | catalytic convertors |
Mn | decomposition of H2O2 |
What are the coloured compounds affected by? | Metal
Oxidation State
Ligands
Co ordination number
(Size of the energy gap between d orbitals) |
What ligands are required for optical isomerism | 3 bidentate
2 bidentate/ 2 single
1 hexdentate |
What are the properties of optical isomerism? | Cannot superimpose
rotates light clockwise
other rotates light anticlockwise |
What are the shapes of molecules and their bond angles? | Linear-180
Tetrahedral-104.5
Square planar-90
Octahedral-90 |
[Pt(NH3)2Cl2] cis-platin | anti cancer drug |
[Ag(NH3)2]+ | Tollens reagent to distinguish aldehydes and ketones |
[Ag(CN)2]- | silver electroplating |
[Ag(S2O3)2]3- | formed in photography unreacted AgX in the film |
Precipitation | soluble ions in seperate compounds are mixed together to produce an insoluble compound |
What do the TM react with? | NaOH(aq) |
Cu2+ | pale blue solution
blue precipitate |
Co2+ | pale pink solution
blue precipitate
pink on standing |
Fe2+ | pale green solution
green precipitate
rusty brown on standing
brown on standing |
Fe3+ | pale yellow solution
rusty brown precipitate |
Why do TM form coloured compounds | white light is passed through and some wavelengths are absorbed, those not absorbed are colours shown |
d block element | where the d sub shell is the highest energy sub shell |
transition element | at least one ion has a partially filled sub shell |
ligand subsitution | a substitution reaction where a ligand in a complex is replaced by another ligand |