transition metals 3.2.5 in papers 1 + 3

only has 1 oxidation state

• Fe3+ is smaller • Fe3+ is more polarising • so more O-H bonds are broken

• full 3d shell • so no transition is possible

a d block element that forms a stable ion with an incompletely filled d-orbital

a central metal ion surronded by ligands

is a molecule or ion that forms a co-ordinate bond with a transition metal by donating a pair of electrons.

the number of co-ordinate bods formed to a central metal ion

• form 1 co-ordinate bond per ligand • H2O • NH3 • Cl-

• have 2 atoms with lone pairs and so can form 2 co-ordinate bonds per ligand • NH2CH2CH2NH2 • C2O4^2-

• can form 6 co-ordinate bonds per ligands • EDTA^4-

• linear , 2 • square plannar, 4 • tetrahedral, 4 • octrahedral, 6

• sqaure plannar • octrahedral

octrahedral

the replacement of monodentate ligands by bidentate or multidentate ligands

• Haem is an iron(II) complex with a multidentate ligand. • Oxygen forms a co-ordinate bond to Fe(II) in haemoglobin, enabling oxygen to be transported in the blood.

• it occupies the sixth position and haemoglobin can no longer transport oxygen • the person is then at risk of dying from oxygen starvation

• blue percipitate

green percipitate

brown percipitate yellow solution

no visible change

white percipitate

turns colourless

green percipitate

green percipitate