Transition Metals

• What is the definition of a transition metal?

  A transition metal is an element that forms at least one stable ion with a partially filled d-subshell.
• What are the general properties of transition metals?

  • Variable oxidation states
  • Form coloured compounds
  • Act as catalysts
  • Form complex ions
  • Exhibit magnetic properties (paramagnetic/diamagnetic)
• What are the exceptions to the general electronic configuration of transition metals?

  • Chromium (Cr): $[Ar] 3d^5 4s^1$
  • Copper (Cu): $[Ar] 3d^{10} 4s^1$
• What are Transition Metals?

  d-block elements that can form at least one stable ion with a partially filled d-subshell
• What d-block elements aren't TM and why?

  Sc and Zn as Sc3+ has an empty d-subshell and Zn2+ has a full d-subshell
• What are the configurations of the outliers?

  Cr: [Ar] 4s1 3d5

  Cu: [Ar] 4s1 3d10
• What are the properties of TM?

  variable oxidation states

  coloured solutions

  good catalysts

  complex ions
• What is a complex ion?

  central metal ion surrounded by ligands bonded by coordinate bonds
• What must ligands have?

  at least one lone pair of electrons
• What are the 3 types of ligands and give examples

  Monodentate: H2O, NH3, OH-, Cl-

  Bidentate: [C2O4]2-, (et)

  Multidentate: EDTA4-, haem
• What are the shapes and bond angles of complex ions?

  Octahedral- 90 degrees

  Tetrahedral- 109.5 drgrees

  Square Planar- 90 degrees (Pt2+ or Ni2+)

  Linear- 180 degrees (Ag+)
• What is haemoglobin?

  protein used to transport oxygen around the body
• What shapes of complex ions can form Geometric Isomers?

  Square Planar- 2 pairs of ligands

  Octahedral- 2 types of ligand, 2 of one type
• What is cisplatin (PtCl2(NH3)2) used for?

  used as a chemotherapy drug
• What shapes of complex ions can form Optical Isomers?

  Octahedral- 3 bidentate ligands
• What is d-subshell splitting?

  when ligands bond with the central metal ion, the d-subshell splits in two
• Explain why complexes formed from TM ions are coloured

  Absorb some frequencies of visible light

  to promote electrons in d-orbitals

  complementary colours are reflected to give colour seen
• What is the energy absorbed formula and what are the units?

  $ΔE=$$hf=$$hc ​/λ$

  ΔE= change in energy (J)

  h= planks constant

  f= frequency (Hz)

  c= speed of light (3*10ms^-1)

  λ= wavelength (m)
• How do you convert form nm to m?

  *10^-9
• What is the size of the ΔE dependant on in d-subshell splitting?

  identity of metal

  OS of metal

  identity of ligand

  coordination number
• What is colorimetry used for?

  to measure the concentration of TM in solution- the more concentrated, the darker the colour, the more light is absorbed
• Describe how a calibration graph is produced and used to find the concentration of a TM complex?

  measure abundance for a range of known concentrations

  plot graph of absorbance vs concentration

  read value of concentration for the measured absorbance
• What is Entropy?

  a measure of disorder
• What is Gibbs Free Energy Equation?

  $ΔG=$$ΔH−TΔS$

  ΔG= gibbs free energy (J)- if <0 the reaction is feasible

  ΔH= enthalpy change (J)- negligible

  T= temperature (K)

  ΔS= entropy change
• What are the oxidation states and colours of the different ions of Vanadium (V)?

  VO2 + (+5)- yellow

  VO 2+ (+4)- blue

  V3+ (+3)- green

  V2+ (+2)- violet
• What is added to reduce Vanadium?

  Zinc
• What do redox potentials tell us?

  how easy an ion is reduces. The least stable ions have the largest redox potentials
• What are Redox Potentials effected by?

  OS

  identity of metal

  identity of ligand- as the standard values are with water ligands

  pH- more acidic, the larger the redox potential
• What are Redox Titrations used for?

  to find the concentration of a reducing or oxidising agent
• What is needed to be added in a Redox Titration and why not HCl?

  excess dilute H2SO4 to ensure sufficient H+ ions to allow reduction of OA

  can't use HCl as the Cl- ions are oxidised by the OA
• What are the two types of Catalysts?

  Hetergeneous- different state to reactants

  Homogeneous- same state as reactants