Chapter 24

• What defines transition metals?

  Elements with an incomplete d-subshell
• How do transition metals differ from d-block elements?

  Scandium and zinc do not have incomplete d-subshells
• What ion does scandium form?

  Sc3+
• What is the electron configuration of Sc3+?

  [Ar] 3d0
• What ion does zinc form?

  Zn2+
• What is the electron configuration of Zn2+?

  [Ar] 3d10
• Which elements are included in the first transition series?

  Titanium to copper
• What is the full electronic configuration of first d-series transition metals?

  • Follows the aufbau principle
  • Electrons occupy lowest energy sub-shells first
  • 4s fills before 3d
• What are the exceptions to the aufbau principle?

  Chromium and copper
• How does chromium's electron configuration differ from expected?

  Cr is [Ar] 3d5 4s1, not [Ar] 3d4 4s2
• How does copper's electron configuration differ from expected?

  Cu is [Ar] 3d10 4s1, not [Ar] 3d9 4s2
• What is the electron configuration of an iron atom?


  1s22s22p63s23p63d64s2
• What is the electron configuration of Fe2+ ion?

  1s22s22p63s23p63d6
• What is the electron configuration of Fe3+ ion?

  1s22s22p63s23p63d5
• What are the general properties of transition metals?

  • Variable oxidation states
  • Form complex ions
  • Form coloured compounds
  • Behave as catalysts

  
• Why do transition metals have variable oxidation states?

  They can lose different numbers of electrons
• How are oxidation states indicated for transition metals?

  Using Roman numerals

  
• What complex ion can chromium(III) form?

  [Cr(NH3)6]3+
• What is a ligand?

  A molecule that forms a coordinate bond
• What is a complex ion?

  A central metal atom with surrounding ligands
• What is the color of the [Cr(OH)6]3- complex?

  Dark green
• What is the color of the [Cr(NH3)6]3+ complex?

  Purple
• What causes the difference in color between [Cr(OH)6]3- and [Cr(NH3)6]3+?

  Ligand field strength and d-orbital splitting
• What is a heterogeneous catalyst?

  In a different phase from reactants
• What is a homogeneous catalyst?

  In the same phase as reactants
• What is the reaction involving manganese(IV) oxide as a catalyst?

  Decomposition of hydrogen peroxide
• What is the structure and bonding in transition element complexes?

  • Central metal ion
  • Ligands form coordinate bonds
  • Ligands donate electron pairs

  
• What is the coordination number?

  Number of coordinated bonds to central atom
• What are mono-dentate ligands?

  Ligands that form one dative bond
• What are bidentate ligands?

  Ligands that form two dative bonds
• What geometries can transition element complexes have?

  • Six-coordinate complexes: octahedral
  • Four-coordinate complexes: tetrahedral or square planar

  
• What is the bond angle in octahedral complexes?

  90 degrees
• What is the bond angle in tetrahedral complexes?

  109.5 degrees

  
• What is the bond angle in square planar complexes?

  90 degrees

  
• What types of isomerism can transition element complexes exhibit?

  • Geometrical (cis-trans) isomerism
  • Optical isomerism
• What is geometrical isomerism in transition metal complexes?

  Different spatial arrangements of ligands
• How does cis-platin affect cancer cells?

  Binds to DNA, preventing replication

  
• What is the effect of cis-platin on healthy cells?

  Can also bind to healthy cells

  
• What is a side effect of cis-platin treatment?

  Hair loss
• What is ligand substitution?

  • Replacement of one ligand in a complex
  • Forms a new, more stable ligand
  • Can be partial or complete