Chemistry of transition element Flashcards
Define transition elements.
D-block elements that form one or more stable ions with an incomplete d subshell.
State the physical properties of transition elements.
High melting points.
High density.
Good conductors of electricity and heat.
State the chemical properties of transition elements.
Variable oxidation states.
Behave as catalysts.
Form complex ions.
Form coloured ions.
Why can transition elements have variable oxidation states?
3d and 4s atomic orbitals are similar in energy.
A similar amount of energy can remove a different number of electrons.
Why transition elements show catalytic behaviour?
They have more than 1 stable oxidation state which allows them to accept and lose electron easily.
They have vacant d orbitals which are energetically accessible.
They can form dative bonds with ligands that results in complex formation.
Define stability constant.
The equilibrium constant for the formation of complex ion in a solvent from its constituent ions or molecules.
Explain why transition metal complexes are coloured.
Degenerate d orbitals split into two energy levels. As light passes through the complex, light energy is absorbed and electrons move to a higher energy level. The colour seen is complementary to the colour of light absorbed by the electrons.
Why different complexes have different colours?
D-d energy gap is different.
Different wavelength of light absorbed.
Define monodentate ligand.
Ligand with one lone pair that forms a coordinate bond with a central metal atom.
Define transition element complex.
Metal atom bonded to one or more ligands.
Define ligand.
A molecule with one or more lone pairs that forms coordinate bond with a central transition element atom.
Define bidentate ligand.
Ligand with two lone pairs of electrons that forms two coordinate bonds to central metal atom.
Explain why a complex is colourless.
D sub-shell is full.
No d electrons excited.
Explain why an isomer is non-polar.
Partial charges cancel out each other.
