Transition Metals

• What is the general property of transition metals?

  They have an incomplete d sub-level in atoms or ions.
• What is the electron configuration of Scandium (Sc)?

  1s²2s²2p⁶3s²3p⁶4s²3d¹
• What is the electron configuration of Copper (Cu)?

  1s²2s²2p⁶3s²3p⁶4s¹3d¹⁰
• What is the electron configuration of Zinc (Zn)?

  1s²2s²2p⁶3s²3p⁶4s²3d¹⁰
• Why is zinc not considered a transition metal?

  Zinc can only form a +2 ion with a complete d orbital.
• What are the characteristics of transition metals?

  • Complex formation
  • Formation of coloured ions
  • Variable oxidation states
  • Catalytic activity
• What is a complex in chemistry?

  A complex is a central metal ion surrounded by ligands.
• What is a ligand?

  A ligand is an atom, ion, or molecule that can donate a lone electron pair.
• What is co-ordinate bonding?

  Co-ordinate bonding involves a shared pair of electrons coming from only one of the bonding atoms.
• What is the co-ordination number?

  The co-ordination number is the number of co-ordinate bonds formed to a central metal ion.
• What are monodentate ligands? Give examples.

  Monodentate ligands can form one coordinate bond per ligand, e.g., H2O, NH3, and Cl^-.
• What are bidentate ligands? Give examples.

  Bidentate ligands have two atoms with lone pairs and can form two coordinate bonds per ligand, e.g., NH2CH2CH2NH2 and C2O4^2-.
• What is the chelate effect?

  The chelate effect refers to the increased stability of a complex when a monodentate ligand is replaced by a bidentate or multidentate ligand.
• What happens when a high concentration of chloride ions is added to an aqueous ion?

  It leads to a ligand substitution reaction and can change the co-ordination number.
• What is the shape of the complex [CuCl₄]^2-?

  The shape is tetrahedral.
• What is the significance of the EDTA complex in environmental applications?

  EDTA complexes can remove poisonous heavy metal ions from rivers.
• How do you calculate the concentration of copper(II) ions in river water using EDTA titration?

  Use the formula: concentration = moles of EDTA / volume of sample.
• What is the formula to calculate moles of EDTA?

  Moles = concentration x volume.
• What is the relationship between the number of moles of EDTA and copper(II) ions in the titration?

  There is a 1:1 ratio between moles of EDTA and moles of copper(II) ions.
• What is the shape of octahedral complexes?

  Octahedral complexes have 90° bond angles.
• What types of isomerism can complex ions show?

  Complex ions can show cis-trans isomerism and optical isomerism.
• How does the formation of coloured ions occur?

  Colour arises from electronic transitions between different d orbitals when visible light is absorbed.
• What happens to the colour of a solution when the ligand or coordination number changes?

  The colour changes due to alterations in the energy split between the d-orbitals.
• What is the formula relating energy difference, frequency, and wavelength of light absorbed?

  ΔE = hv or ΔE = hc/λ
• What is Planck's constant?

  Planck's constant is 6.63 × 10^–34 J s.
• What is the speed of light?

  The speed of light is 3.00 × 10⁸ m s^–1.
• Why do compounds like Scandium and Zinc not exhibit colour?

  They have no d electrons available for electronic transitions.
• What is the effect of changing a ligand on the colour of a complex?

  Changing a ligand alters the energy split between d-orbitals, affecting the colour.
• What colour does a solution appear if it absorbs orange light?

  The solution will appear blue.
• What are the shapes of common complex ions formed by transition metals?

  • Octahedral (with small ligands like H2O and NH3)
  • Tetrahedral (with larger ligands like Cl^-)
  • Square planar (e.g., cisplatin)
  • Linear (e.g., [Ag(NH3)₂]⁺)
• What are the applications of EDTA complexes?

  • Removal of heavy metal ions from rivers
  • Used in shampoos to remove calcium ions
  • Quantitative titrations with metal ions
• What is the ion of Scandium in its ionic form?

  Sc$^{3+}$
• Why does Sc$^{3+}$ not have d electrons available for energy transfer?


  Because it has no d electrons left to move around
• What is the electron configuration of Zn$^{2+}$ and Cu$^{+}$ ions?


  Both have a full d shell, e.g., 3d$^{10}$
• What happens to the oxidation state in the equation [Co(H$_2$O)$_{6}$]$^{2+}$ + 6 NH$_{3}$ → [Co(NH$_{3}$)$_{6}$]$^{2+}$ + 6H$_2$O?


  Only the oxidation state is changing
• What changes occur in the equation when ligands and coordination numbers are involved?

  Both ligand and coordination number are changing
• How does color arise in transition metal complexes?

  It arises from the energy difference between split d orbitals
• What are the equations that link color, wavelength, and frequency of light absorbed with energy difference in d orbitals?

  • ΔE = hv
  • ΔE = hc/λ
  • v = frequency of light absorbed (s$^{-1}$ or Hz)
  • h = Planck’s constant (6.63 × 10$^{-34}$ J s)
  • c = speed of light (3.00 x 10$^{8}$ m s$^{-1}$)
  • λ = wavelength of light absorbed (m)
• If a solution appears blue, what color light does it absorb?

  Orange light
• What is the energy difference ΔE for a blue solution that absorbs orange light with a frequency of 5 x 10$^{14}$ s$^{-1}$?


  ΔE = 3.32 × 10$^{-19}$ J