5.3 Transition Elements

• D-block elements?


  where d-subshell is of the highest energy
• Transition element?


  a d-block element that have an ion with an incomplete d-subshell
• D-block element?


  Sc3+ and Zn2+ are the only ones which arent also transition metals as they have complete d subshells
• Properties of Transition metals:

  -existence of more than one oxidation state, Fe2+, Fe3+

  -formation of coloured ions

  -catalytic behaviour
• Complex ion:

  consists of a central metal ion bonded to one or more ligands by dative bonds
• Ligand:

  molecule or ion which donates a pair of electrons to form a dative bond with the metal ion

  (monodentate has one lone pair) (bidentate has two lone pairs to donate)
• Monodentate Ligand examples?


  -H2O

  -NH3

  -Cl-

  -CN-
• Bidentate Ligand examples?


  -ethane-1,2-diamine (H2NCH2CH2NH2)

  -ethanedioate ion 2-charge (-OCOCOO-)
• Hexadentate Ligand examples?


  EDTA4- (octahedral molecule)
• Coordination number?


  in a complex ion is the number of coordinate bonds formed between the ligands and the central metal ion
• Coordination 6:

  -forms a molecule with 6 monodentate ligands or 3 bidentate ligands

  -octahedral shape (90' bond angle)
• Coordination 4:

  -2 monodentate ligands

  -forms either tetrahedral(109') or square planar(90')
• Cis-trans isomerism in complexes?


  -only square planar complexes

  -cis has bond angle 90' as they are next to each other

  -trans has bond angle 120' as they are across the molecule
• Cis platin?


  -square planar complex

  -anticancer drug as it binds to the DNA in cancer cells and prevents cell division

  -has unpleasant side effects

  -PtCl2(NH3)2
• Optical isomerism in complexes:

  -occurs in octahedral complexes containing bidentate ligands

  -non super imposable mirror images
• Complexes showing both cis-trans and optical isomerism?


  -occurs in complexes with two bidentate ligands and 2 monodentate ligands

  -only the cis isomer shows optical isomerism