Unit One, Chapter Eight - Colours Of Transition Metals And Catalysts Flashcards
How can transition metals act as catalysts?
Due to them having variable oxidation states, they have d orbitals available to form intermediate complexes on the catalyst active sites
What is a heterogeneous catalyst?
A catalyst in a different state to the reactants
What is a homogeneous catalyst?
A catalyst in the same state as the reactants
What is a catalyst?
Catalysts speed up chemical reactions by providing an alternative pathway of lower activation energy
What is ultraviolet spectroscopy used for?
To determine the concentration of the ions in a complex that absorbs in the ultraviolet region
What is colorimetry used for?
To determine the concentration of ions in a complex that absorbs in the visible region
Strong field ligands are more likely to absorb in the…
Ultraviolet region
Weak field ligands are more likely to absorb in the…
Visible region
What is the difference between weak field ligands and strong field ligands?
Weak field ligands have less orbital splitting, strong field ligands have more orbital splitting
What is the spectrochemical series?
I - < Br- < Cl- < F- < H2O < NH3 < CN -
(Weak) (strong)
The greater the splitting …
… The more energy is required to promote an electron from the ground state to the excited state
What is shown by the spectrochemical series?
The degree of ability of ligands to cause splitting
The size of the split between the split sets of d orbitals determines…
…The colour produced by the compound or complex
What factors can influence the size of the energy gap between sets of d orbitals?
- The transition metal ion
- The oxidation state of the transition metal
- The type of ligand
When a d subshell is spit, what is it split into?
Two distinct sets of orbitals that have a difference in energy between them. These sets are called the excited state and the ground state
