transition elements

• They are called 'd-block' elements because the subshell being filled across this series is the 3D subshell.
• transition metals/elements

  an element whose atoms have an incomplete (partially filled )d subshell or form positive ions with an incomplete (partially filled ) d subshell
• zinc is not a transition element
• a transition element is an element that forms at least one stable oxidation state with a partially filled d subshell
• physical properties of transition metals

  • High electrical and thermal
  • conductivity
  • High melting point
  • Malleable
  • High tensile strength
  • Ductile
  • Fe, Co and Ni are ferromagnetic
• chemical properties of transition metals

  • Form compounds with more than one oxidation number
  • Form a variety of complex ions
  • Form coloured compounds
  • Act as catalysts
• transition metal 


  An element that forms at least one stable ion with a partially filled d subshell.
• A Zn atom and it’s only ion, Zn2+, have complete d- subshells
• The 3d and 4s sub-levels have very similar energies. Therefore, the ionisation energies of d-block elements are very similar
• Dative (Coordinate) bond:


  A covalent bond in which both the shared electrons are provided by one of the atoms.
• Ligand

  A chemical species that uses a lone pair of electrons to form a coordinate bond with a metal ion.
• Ligands may have a charge or be neutral
• Labelling complex ions

  • Ligand (H2O)
  • Dative (Coordinate) bond
  • Central metal ion (Fe)
  • Coordination number (6)
  • Charge on a complex
  • Shape of complex
• Polydentate ligand


  A chemical species that has more than one lone pair available to

  form a coordinate bond with the central metal ion.
• Chelate complex

  A complex that contains at least one polydentate ligand.
• the properties of transition elements can be largely related to the presence of partially filled 3d subshells and the involvement of 3d electrons in bonding and reactions
• transition elements form positive ions
• the 4s electrons are always removed before the 3d electrons when an ion is formed
• from sc to mn there is an increase in the total number of electrons in the 4s and 3d subshell so the max oxidation state increases
• as the nuclear charge increases from left to right across the transition element series and the 3d electrons are more strongly attracted it becomes more difficult to reach the highest oxidation states towards the right hand side of the series
• All transition elements (except scandium) show oxidation state +2. This is because they have 2 electrons in the 4s subshell and removal of these generates an oxidation state of 2+