Chapter 24 Flashcards
In what order do transition metals lose electrons?
Electrons are lost from the 4s orbital followed by the 3 d orbital
What are transition metals?
D block elements which form at least one ion with a partially filled d orbital. Examples are scandium(Sc3+) and zinc(Zn2+).
Properties of transition metals
Form compounds with different oxidation states
Form coloured compounds
Elements and compounds can act as catalysts
What is a ligand?
Molecule or ion which donates an electron pair to the central metal ion to form a coordinate bond.
What is the coordination number?
Number of coordinate bonds attached to the central metal ion
What is a monodentate ligand?
Donates one pair of electrons to a central metal ion
What is a bidentate ligand?
Ligand which can donate 2 pairs of electrons to the central metal ion
What is the shape and bond angle of a 6 coordinate complex ion?
Octahedral with a bond angle of 90
What is the shape and bond angle of a 4 coordinate complex ion?
Its more commonly tetrahedral with an angle of 109.5.
It can be square planar if it is platinum
What types of isomerism can complex ions display?
Cis-trans
Optical
What is Ligand substitution?
When one ligand in a complex ion is replaced by another ligand
Ligand substitution of NH3 and Cu
Reaction:
[Cu(H2O)6]^2+ + 4NH3 —> [Cu(NH3)4(H2O)2]^2+ + 4H2O
Colour change:
Pale blue to dark blue
A Cu(OH)2 precpiapte can form in the first stage of reaction. It will then dissolve in excess ammonia to form a dark blue solution. Its colour is a pale blue.
Ligand substitution of Cl and Cu
[Cu(H2O)6]^2+ + 4Cl^- —>[Cu(Cl)4]^2- +6H2O
Colour change:
Pale blue to yellow, green solution may form as an intermediate
How is [Cu(H2O)6]^2+ formed?
Copper sulfate is dissolved in water
How is [Cr(H2O)6]3+ formed?
Chrome alum is dissolved in water
