Transition Flashcards
Monodentate
Water, ammonia, chloride, cyanide, hydroxide.
Bidentate
Ethandioate
1,2 -diamnioethane
Multidentate
EDTA-4
Porferin
Square plAnar
Cisplatin
What are the general properties of transition metals as a result of their incomplete d-sub level
Variable oxidation states
Catalytic action
Coloured compounds
Formation of complexes
Ligand
Particle with lone pair of electrons that bonds to metals by a co ordinate bond
Complex
Metal ion with co-ordinately bonded ligands
Co ordinate number
Number of co ordinate bonds from ligands to metal ion
What is the formula and colour of Fe2+ in aqueous solution ?
[Fe(H2O)6]2+(aq)
Green
What is the formula and colour of Fe2+ with NaOH?
Fe(H2O)4(OH)2 (s)
Green ppt goes brown on standing in air
What is the formula and colour of Fe2+ in an excess of NaoH(aq)
Fe(H2O)4(OH)2 (s)
No further change small amount
What is the formula and colour of Fe2+ with NH3 (aq)
Fe(H2O)4(OH)2 (s)
Green ppt goes brown on standing in air
What is the formula and colour of Fe2+ with an excess of NH3 (aq)?
No further change
What is the formula and colour of Fe2+ with Na2Co3(aq)
FeCO3 (s)
Green ppt
What is the formula and colour of Cu2+ in aqueous?
[Cy(H2O)6]2+ (aq)
Blue solution
What is the formula and colour of Cu2+ with NaOH
Cu(H2O)4(OH)2 (s)
Blue ppt
What is the formula and colour of Cu2+ with an xs of NaOH?
No further change
What is the formula and colour of Cu2+ with NH3 (aq)?
cu(H2O)4(OH)2 (s)
Blue ppt
What is the formula and colour of Cu2+ with an XS if NH3?
[Cu(H2O)2(NH3)4]2+ (aq)
Deep blue solution
What is the formula and colour of Cu2+ with Na2CO3 (aq) ?
CuCO3 (s)
Blue green ppt
What is the formula and colour of Fe3+ in aqueous?
[Fe(H2O)6]3+ (aq)
Purple solution
May appear yellow brown due to some [Fe(H2O)5(OH)]2+ (aq)
What is the formula and colour of Fe3+ with NaOH?
Fe(H2O)3(OH)3 (s)
Brown ppt
Maybe orangery
What is the formula and colour of Fe3+ with XS NaOH?
No further change
What is the formula and colour of Fe3+ with NH3 (aq)
Fe(H2O)3(OH)3 (s)
Brown ppt
What is the formula and colour of Fe3+ with excess NH3(aq)?
No further change
What is the formula and colour of Fe3+ with Na2CO3(aq)?
Fe(H2O)3(OH)3(s)
Brown ppt
CO2 gas evolved
What is the formula and colour of Al3+ in aqueous?
[Al(H2O)6]3+ (aq)
Colourless solution
What is the formula and colour of Al3+ with NaOH?
Al(H2O)3(OH)3 (s)
White ppt
What is the formula and colour of Al3+ with Xs NaOH?
[Al(OH)4]- (aq)
Colourless solution
What is the formula and colour of Al3+ with NH3 (aq)?
Al(H2O)3(OH)3 (s)
White ppt
What is the formula and colour of Al3+ with Xs NH3 (aq)?
No further change
What is the formula and colour of Al3+ with Na2CO3(aq)
Al(H2O)3(OH)3 (s)
White ppt
CO2 gas evolved
4 main features of transition metals.
Variable oxidation states
Colour
Catalysis
Complex formation
When is a complex transition metal ion formed?
When a transition metal ion is surrounded by ligands, bonded by co-ordinate bonds
Lewis base
Lone pair donor
Lewis acid
Lone pair acceptor
Why does the ligand act as a Lewis base and the metal ion act as a Lewis acid in complex ion?
Ligand is donating a lone pair and the metal ion is accepting it
Why are CN- and CO toxic?
They prevent oxygen being transported around the body
When can cis-teams isomerism occur?
In octahedral and square planar complexes where there are two ligands of one type different to other ligands
When does optical isomerism occur in complexes?
In an octahedral complex with three bidentate ligands
Why is HCl an unsuitable as as the medium for which KMnO4 reacts?
MnO4- would oxidise the Cl-, so the total volume of KMnO4 would be affected.
Why is concentrated H2SO4/HNO3; an unsuitable as as the medium for which KMnO4 reacts?
They are oxidising agents so effect the volume of KMnO4 required in the titration.
Why is Ethanoic acid an unsuitable as as the medium for which KMnO4 reacts?
It’s too weak an acid and would not provide enough H+ ions.
What are the reactions of metal aqua ions?
Hydrolysis
Substitution
Redox
Ligand
Atom, ion or molecule which can donate a lone electron pair
Complex ion
Central metal ion surrounded by co-ordinately bonded ligands which co-ordination number exceeds oxidation state
Co-ordination number
The number of co-ordinate bonds formed to a central metal ion
When doing colorimetry, why is it important that the container for each sample has the same dimensions?
Absorption depends on distance traveled through solution
Why is a coloured filter used in colorimetry ?
To select the colour or wavelength that is almost strongly absorbed by the sample
Why might a colorimetric method be chosen in preference of a titration?
Quicker to measure extracted samples than to titrate
How does the precipitate become dry in a desiccator?
Water vapour of precipitate is absorbed by the dying agent.
Explain the term complex
Transition metal ion surrounded by one or more coordinately bonded ligands.
