Ionic and Covalent Bonds - Key Concepts

Introduction

• Chemical Bonds: Bind molecules together and are primarily categorized as ionic or covalent.
• Ionic Bonds:
  • Involve the transfer of electrons from one atom to another.
  • Require one electron donor (metal) and one electron acceptor (nonmetal).
• Covalent Bonds:
  • Involve the sharing of electrons between atoms.
  • Occur between atoms with similar electronegativity.

Ionic Bonding

• Definition: Complete transfer of valence electrons resulting in oppositely charged ions.
• Characteristics:
  • Metal loses electrons, becoming a positively charged cation.
  • Nonmetal accepts electrons, becoming a negatively charged anion.
  • The net charge of the ionic compound must be zero.
• Energy Consideration:
  • Usually endothermic and unfavorable by ionization energy and electron affinity.
  • Favorable due to electrostatic attraction between oppositely charged ions.

Example 11: Chloride Salts

• Sodium atom donates 1 electron to a chlorine atom, forming sodium cation and chlorine anion.
• Magnesium atom donates 2 electrons, requiring two chlorine atoms to accept them, maintaining a net zero charge.

Covalent Bonding

• Definition: Sharing of electrons between atoms.
• Characteristics:
  • Occurs primarily between nonmetals.
  • Atoms have similar electronegativities.
  • Include sigma and pi orbital interactions, forming single, double, triple, and quadruple bonds.

Example 22: PCl3

• Phosphorus shares 3 unpaired electrons with 3 chlorine atoms, achieving octet configuration.

Bonding in Organic Chemistry

• Types of Bonds: Ionic, covalent, and polar covalent (intermediate between ionic and covalent).
• Polarity:
  • Depends on symmetry and differences in electronegativity.
  • A spectrum from ionic (polar) to covalent (nonpolar), with polar covalent in the middle.
• Importance:
  • Ionic bonds: Synthesis of specific organic compounds.
  • Covalent bonds: Carbon-based compounds, allowing electron sharing and complex molecular structures.

References

• Vollhardt, K. Peter C., and Neil E. Schore. "Organic Chemistry Structure and Function."
• Petrucci, Ralph H. "General Chemistry: Principles and Modern Applications."
• Brown, Theodore L., Eugene H. Lemay, and Bruce E. Bursten. "Chemistry: The Central Science."

Practice Problems

1. Determine if compounds are ionic or covalent based on given molecules.
2. Identify the nature of bonds in reactions and between specific atoms in a compound.

Solutions

1. Sequence of ionic and covalent bonds in given examples.
2. Nature of reactants and products (ionic or covalent) in specified reactions.