Transition Metals Flashcards
How are d-block transition metals defined?
Transition metallic elements that have an incomplete d subshell in at least one of their ions.
What are ligands?
Ligands are electron donors and may be negative ions or molecules with non-bonding pairs of electrons.
What is a dative covalent bond?
A covalent bond where both electrons of the shared pair come from the same atom.
When is a ligand described as monodentate?
If it uses just one atom to bind to the central metal.
What is the co-ordination number?
The total number of bonds from the ligands to the central transition metal atom/ion.
How are water ligands written in a complex ion?
(OH₂)
What is the name for the CN⁻ ligand in a complex ion?
Cyanido.
What is the name for the C₂O₄²⁻ ligand in a complex ion?
Oxalato.
What is the name for iron in a negative complex ion?
Ferrate.
What is the name for copper in a negative complex ion?
Cuprate.
What is the name for silver in a negative complex ion?
Argentate.
What is the name for tin in a negative complex ion?
Stannate.
What is the name for gold in a negative complex ion?
Aurate.
What is the name for lead in a negative complex ion?
Plumbate.
What is the theory that explains how colour arises in transition metal complexes?
Crystal field theory.
Explain fully how colour arises in transition metal complexes.
The degenerate 3d orbitals of the transition metal atom are split by the action of ligands approaching and binding to it.
This means that they are no longer degenerate - 2 orbitals have a higher energy and 3 have a lower energy.
Electrons present in any of the lower energy d orbitals can absorb energy and get promoted to one of the higher energy d orbitals. This is known as a d-d transition.
If the energy absorbed is equal to a wavelength of light in the visible spectrum, the complementary colour will be transmitted.
What does the colour of light absorbed by a transition metal complex depend upon?
The extent to which the d orbitals have been split.
What 3 factors does the extent to which the d orbitals split depend upon?
The metal involved
The oxidation state of the metal
The nature of the ligand
What is oxidation?
Oxidation is when there is an increase in oxidation number and a loss of electrons.
What is reduction?
Reduction is when there is a decrease in oxidation number and a gain of electrons.
What are compounds containing metals in high oxidation states often used as?
Oxidising agents.
What are compounds containing metals in low oxidation states often used as?
Reducing agents.
What are the 3 neutral ligands?
NH₃ (ammonia), CO (carbon monoxide, H₂O (water)
What is the series that places ligands in order of their ability to split d orbitals?
Spectrochemical series.
What can transition metals and their compounds act as?
Catalysts.
What are heterogeneous catalysts?
Catalysts that are in a different state to the reactants.
What are homogeneous catalysts?
Catalysts that are in the same state as the reactants.
