Chemical Bonding and Intermolecular Forces: Summary

Chemical Bonding and Intermolecular Forces

Ionic Bonding

  • Chemical Bond: Mutual electrical attraction between nuclei and valence electrons of different atoms.
  • Atoms form bonds to achieve a stable electron arrangement, often an octet.
  • Valence Electrons: Electrons in the outer energy level, responsible for chemical properties.
  • Ionic Bond: Electrostatic attraction between oppositely charged ions (cation and anion).
  • Formed between metal and non-metal atoms.
  • Metals lose electrons to become cations (+).
  • Non-metals gain electrons to become anions (-).
  • Electron-dot notation: Representation of valence electrons around an element's symbol.
  • Ionic Compounds: Substances consisting of chemically bonded ions with high melting and boiling points, crystal structures, and conductivity in molten or aqueous states.

Covalent Bonding

  • Covalent Bond: Bonding between nonmetal atoms through sharing of electrons.
  • Achieves stability similar to noble gases.
  • Shared electrons are called shared pair or bonding pair.
  • Types of Covalent Bonds:
    • Single
    • Double
    • Triple
  • Covalent compounds can be solids, liquids, or gases with lower melting points, typically not conducting electricity and low solubility.

Intermolecular Forces (IMFs)

  • Weak forces of attraction between molecules.
  • Types:
    • London Dispersion Forces (LDF): Temporary attractive force due to temporary dipoles in nonpolar molecules.
    • Dipole-Dipole Interactions: Occur between polar molecules with permanent dipole moments.
    • Hydrogen Bonding: Special IMF between molecules with H bonded to F, O, or N.
  • Hydrogen bonding results in properties like high boiling and melting points and high surface tension in water.

Metallic Bonding

  • Metallic Bond: Electrostatic attraction between positive metal ions and delocalized electrons.
  • Valence electrons detach and move around metal atoms, delocalized.
  • Metals have electrical and thermal conductivity, ductility, and malleability due to delocalized electrons.
  • Alloys are mixtures of metals with enhanced properties.

Molecular Geometry

  • Molecular Geometry: 3D arrangement of atoms in a molecule.
  • VSEPR Theory: Predicts molecular shape based on minimizing electron pair repulsion.
  • Bond Angle: Angle between two bonds with a common atom.
  • Common Geometries: Linear, Trigonal Planar, Tetrahedral, Trigonal Bipyramidal, Octahedral.

Polarity in Molecules

  • Polarity depends on electronegativity difference between atoms.
  • Electronegativity: Ability of an atom to attract electrons.
  • Polar molecules have charged ends (+ and -).
  • Molecular geometry affects overall polarity.
  • Examples:
    • H−ClH-Cl polar molecule
    • CO2CO_2 nonpolar molecule

Naming Anions and Cations

  • Anions: Add "-ide" suffix to the element name (e.g., Chloride, Oxide).
  • Cations: Metal name remains the same, add "ion" (e.g., Potassium ion).