15.2.1 Origin of Color

• Transition metals are elements that have incomplete d-orbitals
• What is one key characteristic of transition metals?

  Ability to form colored complexes
• Transition metals exhibit variable oxidation states due to their partially filled d-orbitals.
• Match the metal type with its unique properties:

  Transition Metals ↔️ Forms colored complexes, variable oxidation states

  s-Block Metals ↔️ Highly reactive, forms ionic compounds

  p-Block Metals ↔️ Wide range of properties, from semiconductors to nonmetals
• Complex ions are formed when a central metal ion binds to one or more ligands through coordinate covalent bonds.
• What type of bond is formed between a metal ion and a ligand in a complex ion?

  Coordinate covalent bond
• Coordinate covalent bonds are formed when ligands donate lone pairs of electrons to the metal ion.
• What is the general electronic configuration of transition metals with partially filled d-orbitals?

  $[noble gas] ns^{2} (n - 1)d^{x}$
• Transition metals are elements with incomplete d-orbitals
• Transition metals form colored complexes and have variable oxidation states.
• What type of compounds do s-block metals typically form?

  Ionic
• Steps in the formation of complex ions

  1️⃣ Ligands approach the metal ion

  2️⃣ Coordinate covalent bonds form

  3️⃣ The metal ion becomes part of a complex with characteristic geometry
• Match the components of $[Cu(NH_{3})_{4}]^{2 + }$ with their roles:


  Cu²⁺ ↔️ Central metal ion

  NH₃ ↔️ Ligands
• What type of bonds are formed between ligands and a central metal ion in complex ions?

  Coordinate covalent
• In the complex ion $[Cu(NH_{3})_{4}]^{2 + }$, the ligand is NH₃
• What is the coordination number of Cu²⁺ in $[Cu(NH_{3})_{4}]^{2 + }$?


  4
• In $[Cu(NH_{3})_{4}]^{2 + }$, Cu²⁺ is the central metal ion
• What is the role of NH₃ in $[Cu(NH_{3})_{4}]^{2 + }$?


  Ligand
• The coordination number of Cu²⁺ in [Cu(NH_{3})_{4}]^{2 + }</latex> is 4
• Complex ions are formed when a central metal ion binds to ligands through coordinate covalent bonds.
• Steps in the formation of complex ions:

  1️⃣ Ligands approach the metal ion

  2️⃣ Coordinate covalent bonds form as ligands donate electron pairs

  3️⃣ The metal ion becomes part of a complex ion with a characteristic geometry
• Which ligands are present in the complex ion $[Cu(NH_{3})_{4}]^{2 + }$?


  NH₃
• The complex ion $[Cu(NH_{3})_{4}]^{2 + }$ has a square planar geometry
• What causes d-orbital splitting in transition metal complexes?

  Ligands
• In tetrahedral complexes, the $t_{2}$ orbitals have higher energy than the $e$ orbitals.
• In octahedral complexes, the $e_{g}$ orbitals are higher in energy
• What type of transitions are responsible for the color of transition metal complexes?

  d-d Electronic transitions
• The energy difference between d-orbitals determines which wavelengths of light are absorbed.
• In which ion does an electron transition from $t_{2g}$ to $e_{g}$ result in color absorption in the visible spectrum?


  $Ti^{3 + }$
• Transition metals have partially filled d-orbitals in their electronic configurations.
• What are two unique properties of transition metals?

  Colored complexes, variable oxidation states
• Match the metal type with its unique properties:

  Transition Metals ↔️ Forms colored complexes

  s-Block Metals ↔️ Highly reactive
• What characterizes the electronic configurations of transition metals?

  Partially filled d-orbitals
• Transition metals form colored complexes due to their variable oxidation states.
• What is the defining feature of transition metals according to their electronic configuration?

  Incomplete d-orbitals
• p-Block metals have a wide range of properties due to their ns²npˣ electronic configuration.
• What is the range of x in the electronic configuration of transition metals?

  1 to 9
• Steps in the formation of complex ions with ligands

  1️⃣ Ligands approach the metal ion

  2️⃣ Coordinate covalent bonds form

  3️⃣ The metal ion becomes part of a complex ion
• Complex ions are formed when a central metal ion binds to one or more ligands through coordinate covalent bonds.
• The complex ion $[Cu(NH_{3})_{4}]^{2 + }$ has a square planar geometry and exhibits high stability.