3.2.5.1: General Properties of Transition Metals

• Transition metals are defined as:

  Elements (metals) with an incomplete d-subshell that can form at least 1 stable ion with an incomplete d-subshell
• Scandium (Sc) & zinc (Zn) are not classified as transition metals because:

  • They do not have incomplete d sub-shells (Sc is empty, Zn is full)
  • Their ions do not have incomplete d sub-shells
• Which two transition metals do not follow the trend in electron configuration?

  Chromium (Cr)

  Copper (Cu)
• Why do chromium & copper not follow the trend in electron configuration?

  Electron that would be in 4s subshell is promoted to 3d subshell

  … Because half-filled (in Cr) & fully filled (in Cu) (3)d-subshell is more energetically stable than fully filled 4s subshell
• What are the (4) chemical properties of transition metals?

  • Variable oxidation states
  • Form coloured compounds
  • Catalytic activity/behaviour
  • Form complex ions
• Define complex:

  Central metal atom/ion surrounded by ligands
• Define: Ligand:

  Molecule or ion that can form a coordinate bond with a transition metal by donating a pair of electrons
• Define: Co-ordination number

  No. of coordinate bonds to complex