5.6 Transition Elements

• What defines transition metals?

  Incomplete d-subshell and stable ions
• How do transition metals differ from d-block elements?

  Scandium and zinc do not fit the definition

  
• What ion does scandium form?

  Sc³⁺
• What ion does zinc form?

  Zn²⁺
• Which elements are in the first transition series?

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

  • Follow Aufbau Principle
  • 4s fills before 3d
  • Abbreviate first five subshells as [Ar]
• What is the electron configuration of chromium?

  [Ar] 3d⁵ 4s¹
• What is the electron configuration of copper?

  [Ar] 3d¹⁰ 4s¹
• Why do chromium and copper have different electron configurations?

  To achieve stable half-full and full d-subshells
• What are the common oxidation states of iron?

  Fe²⁺ and Fe³⁺
• What are the general properties of transition elements?

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

  
• What does it mean for transition elements to have variable oxidation states?

  They can form more than one positive ion
• How are oxidation states indicated for transition metals?

  Using Roman numerals
• What is a complex ion?

  A central metal atom with surrounding ligands
• What is a ligand?

  A molecule that donates electron pairs
• How do ligands bond to transition metals?

  By forming coordinate bonds
• What are the types of ligands based on bonding capabilities?

  • Monodentate: one dative bond
  • Bidentate: two dative bonds
• What is the coordination number?

  Number of coordinate bonds to metal
• What is the geometry of six-coordinate complexes?

  • Octahedral shape
  • Bond angles of 90 degrees
• What shape do four-coordinate complexes often adopt?

  Tetrahedral shape
• What are the bond angles in tetrahedral complexes?

  109.5 degrees

  
• What ligands commonly form tetrahedral complexes?

  Chloride ions

  
• What is the geometry of four-coordinate complexes that adopt a square planar shape?

  • Square planar shape
  • Bond angles of 90 degrees

  
• What types of isomerism can transition element complexes exhibit?

  • Geometrical (cis-trans) isomerism
• How does cis-platin affect cancer cells?

  By binding to DNA in cancer cells

  
• What is the difference between cis-platin and trans-platin?

  Cis-platin has beneficial medical effects

  
• What conditions allow for geometrical isomerism in complexes?

  • Two pairs of different ligands
  • Square planar or octahedral geometry
• What is the significance of the arrangement of different ligands in geometrical isomerism?

  Determines whether it is cis or trans isomer
• What happens if the two different ligands are adjacent in a complex?

  It is the 'cis' isomer
• What happens if the two different ligands are opposite each other in a complex?

  It is the 'trans' isomer

  
• What type of isomerism do square planar and octahedral complexes exhibit with two pairs of different ligands?

  Cis-trans isomerism
• How does cis-platin affect cancer cells?

  It binds to DNA in cancer cells

  
• Why can't trans-platin be used in cancer treatment?

  It does not bind effectively to DNA

  
• What type of complex is cis-platin?

  Square planar transition element complex
• What condition must a complex ion meet to display geometric isomerism?

  It must have two different ligands
• What does the term 'cis' refer to in geometric isomerism?

  Ligands are next to each other
• What does the term 'trans' refer to in geometric isomerism?

  Ligands are opposite each other
• In the cis isomer of [Co(NH$_{3}$)(H$_{2}O$)] what is the arrangement of the water ligands?


  They are next door to each other
• In the trans isomer of [Co(NH$_{3}$)(H$_{2}O$)] what is the arrangement of the water ligands?


  They are opposite each other
• What is optical isomerism in octahedral complexes?

  Non-superimposable mirror images