3.2.6.1 Formation of Complex Ions

• What is a complex ion?

  Metal ion with ligands
• What does the coordination number in a complex ion refer to?

  Number of ligands bonded
• What is the coordination number in a complex ion?

  Number of ligands bonded
• What are the main types of ligands that can form complex ions?

  Neutral, monovalent, polyatomic, chelating
• Coordinate covalent bonds in complex ions involve electron donation from ligands to the central metal ion.


  True
• In a coordinate covalent bond, ligands provide both electrons
• What effect does a higher positive charge on the central metal ion have on complex ion formation?

  Stronger attraction
• What effect do bulky ligands have on complex ion formation?

  Limit ligand binding
• What are ligands in a complex ion?

  Molecules or ions bonded to metal ion
• What is the term for the entire assembly of a central metal ion and its ligands?

  Coordination complex
• In complex ions, coordinate covalent bonds occur when ligands attach to the central metal ion
• Chelating ligands form multiple bonds with the central metal ion for higher stability.


  True
• What do ligands provide in a coordinate covalent bond with the metal ion?

  Both electrons
• A higher positive charge on the central metal ion leads to stronger attraction
• What does the equilibrium constant (K) measure for complex ion formation?

  Stability
• Why is [Cu(NH3)4]2+ more stable than [Cu(H2O)4]2+?

  NH3 has higher electronegativity
• Match the variables in the stability constant formula with their meanings:

  M^{n+} ↔️ Central metal ion

  L ↔️ Ligand

  [ML_x]^{(n-x)+} ↔️ Complex ion
• Ligands with higher electronegativity form more stable complex ions.


  True
• Complex ions are used in analytical chemistry to detect metal ions in samples.


  True
• Which complex ion is used to remove zinc ions from water in environmental remediation?

  [Zn(EDTA)]2-
• Match the characteristic of a complex ion with its description:

  Central Metal Ion ↔️ Positively charged metal ion

  Ligands ↔️ Molecules or ions bonded to the metal
• In a complex ion, ligands are bonded to the central metal ion through coordinate bonds.
• The coordination number in a complex ion refers to the number of ligands bonded to the central metal ion.

  True
• In the complex ion [Cu(NH3)4]2+, which ligand forms a coordinate covalent bond with the copper ion?

  Ammonia
• A coordinate covalent bond is formed when both electrons in a shared pair are provided by a single atom.


  True
• In the complex ion [Cu(NH3)4]2+, each ammonia ligand donates two electrons to form a coordinate covalent bond with the copper(II) ion.


  True
• Ligands with higher electronegativity form more stable complex ions.

  True
• The central metal ion is the positively charged ion at the center of the complex
• The coordination number is the number of ligands bonded to the central metal ion
• Which chelating ligand forms two coordinate covalent bonds with the copper(II) ion in [Cu(en)2]2+?

  Ethylenediamine
• Polyatomic ions bond via negative charges
• In complex ions, coordinate covalent bonds occur when ligands attach to the central metal ion
• Which ligand donates electrons to form a coordinate covalent bond with copper(II) in [Cu(NH3)4]2+?

  Ammonia
• The complex ion [Cu(NH3)4]2+ is more stable than [Cu(H2O)4]2+ because ammonia has higher electronegativity than water.


  True
• The stability constant (K) is the equilibrium constant for the formation of a complex ion.


  True
• The stability constant (K) is expressed as the ratio of the complex ion concentration to the product of the metal ion and ligand concentrations.


  True
• Smaller metal ions form more stable complex ions because they can accommodate more ligands
• The complex ion [Cu(NH3)4]2+ is more stable than [Cu(H2O)4]2+ because ammonia ligands have higher electronegativity
• The complex ion [Pt(NH3)2Cl2], also known as cisplatin, is used as an anti-cancer drug.
• In a complex ion, ligands are molecules or ions that are bonded to the central metal