gen chem itrermolecularforces

• PHASE


  A homogeneous part of a system in interacting with other parts of the system but separated from these other parts by well-defined boundaries
• CONDENSED PHASES


  Liquids and solids
• INTRAMOLECULAR FORCES


  Forces that hold atoms together in a molecule
• INTERMOLECULAR FORCES


  Attractive forces between molecules
• INTERMOLECULAR FORCES


  Determine the state of matter and their physical properties such as melting/boiling point etc.
• INTRAMOLECULAR FORCES


  Determine chemical behavior of a substance
• Types of Intermolecular Forces


  • London Dispersion force
  • Dipole – dipole force
  • Hydrogen bond
• KINETIC MOLECULAR THEORY


  • Explains the states of matter and is based on the idea that matter is composed of tiny particles that are always in motion
• KINETIC MOLECULAR THEORY POSTULATES


  • Particles of a gas are in constant motion and collide with both one another and the container
  • The gas is mostly empty space
  • Pressure is exerted when the particles hit the sides of the container
  • We assume that the particles do not interact with each other
  • Average kinetic energy is proportional to the temperature
• LIQUIDS


  • Much more difficult to compress than gases
  • Denser than gases under normal conditions
  • Molecules are held together by attractive intermolecular forces
• SOLIDS


  • Incompressible
  • No freedom of motion
  • Vibration
• PROPERTIES OF MATTER


  • Volume/Shape
  • Density
  • Compressibility
  • Motion of Molecules
• LONDON DISPERSION FORCES


  • Also called as Van der Waals Forces
  • The weakest intermolecular forces and temporary intermolecular forces between particles
  • These are attractive forces between temporary dipole and induced dipole
• London Dispersion Forces exist in everything
• Molecules where London Dispersion Forces are dominant


  • POLAR MOLECULES: HF, CO2
  • NON-POLAR MOLECULES: F2, Cl2, Br2, I2
• Larger atoms


  Stronger London Dispersion Forces
• DIPOLE-DIPOLE FORCES


  Dipole-dipole interactions exists when partially positive atom of one polar molecule is attracted to partially negative atom of the second molecules
• HYDROGEN BONDING


  • Exists in polar molecules that contains H atom covalently bonded to highly electronegative atoms such as N, O, and F
  • It is the strongest intermolecular forces
• Hydrogen bonding does not exist in non-polar molecules like CH4, C2H6, C3H8 due to small electronegativity difference
• Compounds with Hydrogen Bonding


  • NH3, H2O, HF
• Dipolar-dipolar interactions occur between polar molecules with permanent dipoles.
• London dispersion forces are weak intermolecular forces that arise from temporary fluctuations in electron density around atoms or molecules.
• Hydrogen bonding is a strong type of dipole-dipole interaction that occurs when hydrogen is bonded to highly electronegative atoms like oxygen, nitrogen, or fluorine.
• Dipole-dipole interactions occur between polar molecules with permanent dipoles.
• London dispersion forces are weak intermolecular forces that arise from temporary fluctuations in electron density around atoms or molecules, resulting in instantaneous dipoles.
• London dispersion forces are temporary attractive forces that result from the movement of electrons creating temporary dipoles.
• The strength of the London dispersion forces depends on the size, shape, and electron density distribution of the molecule.
• The strength of the London dispersion forces is proportional to the number of electrons.
• Dipole-dipole interactions occur between molecules with permanent dipoles due to differences in electronegativity.
• The strength of London dispersion forces depends on the size and shape of the molecule, as well as its polarity.
• London dispersion forces are weak attractive forces that arise from temporary fluctuations in electron density around all atoms or molecules.
• Ionic bonds involve the transfer of one or more electrons from an atom to another atom, resulting in the formation of positively charged ions (cations) and negatively charged ions (anions).
• The strength of these forces depends on the size and shape of the particles involved.
• Ionic bonds form between oppositely charged ions (cations and anions) resulting in the transfer of one or more valence electrons from one atom to another.
• Molecules with larger surface areas have stronger London dispersion forces compared to smaller ones.
• Covalent bonds form when two atoms share one or more pairs of valence electrons.
• In general, larger particles have stronger London dispersion forces than smaller ones.
• Nonpolar molecules have weaker London dispersion forces than polar molecules because they do not possess any permanent dipole moment.
• Covalent bonds involve the sharing of pairs of electrons between two atoms.
• Metallic bonds hold metal atoms together by sharing their outermost electrons, forming a sea of delocalized electrons throughout the entire structure.