Flashcards in Transition Metals Deck (43):
Name three bidentate ligands
Name a hexadentate (multidentate) ligand
What shape do tetrachloro ligands make and why?
Tetrahedral because the ions are large so fewer can fit around the central metal ion
What shape is an Ag+ complex?
What shape is a Pt2+ complex?
Why are transition metal complexes coloured?
Electrons can move between d-orbitals, and in a compound the neighbouring atoms make the orbitals have slightly different energies. Electrons absorb energy in the visible region of the spectrum to move between orbitals, so we see a combination of the colours that are not absorbed.
How can colorimetry be used to find the formula of a transition metal complex?
Metal ions and ligands are mixed in different ratios and the ratio that is the same as in the complex will produce the most of the complex so will absorb most light.
What is a transition metal?
An element that forms at least one stable ion with a part full d-shell of electrons
Co(II) and H2O
Cu(II) and H2O
Fe(II) and H2O
Cr(III) and H2O
Fe(III) and H2O
Violet solution - appears brown due to hydrolysis
V(III) and H2O
Al(III) and H2O
Co(II) and NH3
Straw coloured solution
Cu(II) and NH3
Deep blue solution
Co(III) and NH3
Dark brown solution
Cr(III) and NH3
Co(II) and OH-
Cu(II) and OH-
Fe(II) and OH-
Green precipitate - turns brown due to oxidation
Cr(III) and OH-
Light green precipitate [Cr(H2O)3(OH)3]
Green solution [Cr(OH)6]3-
Fe(III) and OH-
Al(III) and OH-
White precipitate [Al(H2O)3(OH)3]
Colourless solution [Al(OH)4]-
Co(II) and Cl-
Cu(II) and Cl-
Co(II) and carbonate ion
Cu(II) and carbonate ion
Fe(II) and carbonate ion
Define heterogeneous catalyst
A catalyst present in a different phase than the reactants (usually a solid while the reactants are gases or liquids)
Define homogeneous catalyst
A catalyst in the same phase as the reactants (where an intermediate species is formed during the reaction)
Define a Lewis acid
An electron pair acceptor
Define a Lewis base
An electron pair donor
Why is hexaaquairon(III) acidic whereas hexaaquairon(II) isn't so much?
The Fe3+ ion is smaller and more highly charged that the Fe2+ ion so it attracts the electrons on the oxygen atoms which weakens the OH bonds in the water molecules which causes H+ ions to be released, making the solution acidic.
How can you distinguish between iron ions?
Add a dilute alkali, which precipitates the hydroxides with obviously different colours
Showing both acidic and basic properties