5.3 - Transition Metals Flashcards
Transition metals
Elements that can form stable ions with an incomplete d sub shell
Why are Sc and Zn d-block elements but not transition metals
Sc^3+ ions have an empty 3d sub-shell and Zn2+ have a completely full subshell
Properties of transition metals
Variable oxidation states
Catalytic action
Coloured compounds
Formation of complexes
Complex ion
Metal ion surrounded by co-ordinately bonded ligands
Coordinate bond
Covalent bond in which both electrons in the shared pair come from the same atom
Coordination no.
No. of coordinate bonds to ligands that surround a transition metal ion
Ligand
An ion/molecule that forms a coordinate bond w/ a transition metal by donating its lone pairs (acts as a base)
Unidentate/monodentate
Ligand that can only form one coordinate bond
Examples of unidentate ligands
H2O NH3 Cl- OH- CN-
Bidentate
Ligand that can form two coordinate bonds by donating two lone pairs to central metal ion
Multidentate
Ligand that can form >1 coordinate bonds
What does coordination no. depend on
Size and electronic configuration of the cation
Size and charge of the ligands
Common coordination no.
6, 4, 2
Octahedral complexes
6 coordinate bonds (90 degrees)
Drawing 3D octahedral complexes
2 on the plane
2 going back into the plane
2 coming out of the plane
Tetrahedral complexes
4 coordinate bonds (109.5 degrees)
Usually chloro complexes
Drawing 3D tetrahedral complexes
2 on the plane
1 going back into the plane
1 coming out of the plane
Square planar complexes
4 coordinate bonds (90 degrees)
Requires TM w/ a 3d8 subshell e.g. Pt
Drawing 3D square planar complexes
2 going back into the plane
2 coming out of the plane
Cis trans isomerism in transition metal complexes
Only occurs in octahedral or square planar
Need two ligands that are different to the rest
Optical isomerism in TM complexes
Occurs in octahedral complexes w/ bidentate ligands
Can also be cis/trans
Highest oxidation no. for Sc
3+
Highest oxidation no. for Ti
+5
highest oxidation no. for V
+5