Physical Science

• IONIC BOND - metal and nonmetal (transfer of electrons)
• COVALENT BOND- nonmetals (sharing of electrons)
• Polarity is important because it determines whether a molecule is hydrophilic or hydrophobic.
• hydrophilic - from the Greek for water-loving
• hydrophobic - from the Greek for water-fearing or water-averse
• LIKE DISSOLVES LIKE - Polarity
• polarity - refers to the distribution of electrons in a molecule, leading to regions of partial positive and negative charges, resulting in the molecule having a dipole moment.
• Molecules - can be polar and nonpolar depending on electronegativity.
• ELECTRONEGATIVITY - A measure of an atom's ability to attract shared electrons to itself.
• Atoms with high electronegativity have a greater tendency to attract electrons compared to those with low electronegativity.
• Difference in electronegativity between two atoms gives an idea of the type of chemical bond that can exist between them.
• INTERMOLECULAR FORCES OF ATTRACTION - Forces that exist between molecules. These forces play a crucial role in determining the physical properties of substances such as boiling point, melting point, viscosity, and solubility.
• BOILING AND MELTING POINT - Substances with stronger intermolecular forces generally have higher boiling and melting points because more energy is required to overcome these forces and transition one phase to another.
• VISCOSITY - Substances with stronger intermolecular forces generally have higher viscosities because the molecules are more tightly bound together and have difficulty sliding past each other.
• BOILING AND MELTING POINT -Substances with stronger intermolecular forces generally have higher boiling and melting points because more energy is required to overcome these forces and transition one phase to another.
• SOLUBILITY - Intermolecular forces also influence solubility, which is the ability of a substance (solute) to dissolve in another substance (solvent) to form a homogeneous mixture (solution).
• Intermolecular forces also influence solubility, which is the ability of a substance (solute) to dissolve in another substance (solvent) to form a homogeneous mixture (solution).
• LONDON DISPERSION FORCES - These are the weakest type of intermolecular force and exist between all molecules. They result from temporary fluctuations in electron distribution within molecules, leading to temporary dipoles.
• types of INTERMOLECULAR FORCES OF ATTRACTION - Ion-Dipole Interaction; Van Der Waals Forces - London Dispersion Forces , Dipole-dipole Interaction (Hydrogen Bonding)
• DIPOLE-DIPOLE INTERACTIONS - These occur between polar molecules. Polar molecules have permanent dipoles due to differences in electronegativity between atoms. The positive end of one molecule is attracted to the negative end of another.
• HYDROGEN BONDING - This is a specific type of dipole-dipole interaction that occurs when a hydrogen atom is bonded to a highly electronegative atom (usually nitrogen, oxygen, or fluorine).
• ION-DIPOLE INTERACTIONS - These occur between an ion and a polar molecule. The charged ion is attracted to the partial charges on the polar molecule.
• MOLECULAR GEOMETRY - Pertains to the three-dimensional arrangement of atoms in a molecule.
• BASIC CONCEPTS - Lewis Electron Dot Structure (LEDS) , Valence Shell Electron Pair Repulsion (VSEPR) Theory
• Lewis electron dot structure - Valence electrons are represented using dot around the symbol of the element.
• VALENCE ELECTRON - Electrons in the outermost shell of an atom. -ELECTRON CONFIGURATION (S, P, D, F)
• LEDS - can be used to show chemical bonding
• KEY IDEAS (VSEPR Theory)

  Electron pairs stay as far apart from each other as possible to minimize repulsion

  Molecular shape is determined by the number of bond pairs and lone pairs around the atom.
• KEY IDEAS (VSEPR Theory) -Electron pairs stay as far apart from each other as possible to minimize repulsion

  -Molecular shape is determined by the number of bond pairs and lone pairs around the atom.

  -Treat multiple bonds as if they were single bonds. (in making prediction)

  -Lone pairs occupy more volume than bond pairs.
• LINEAR - 2 bond pairs and no lone pair
• TRIGONAL PLANAR - 3 bond pairs and no lone pair
• BENT/ANGULAR - 2 bond pairs and 1 or 2 lone pair
• TETRAHEDRAL - 4 bond pairs and no lone pair
• TRIGONAL PYRAMIDAL - 3 bond pairs and 1 lone pair
• TRIGONAL BiPYRAMIDAL - 5 bond pairs and 0 lone pair
• OCTAHEDRAL - 6 bond pairs and 0 lone pair
• POLARITY BASED ON STRUCTURES

  NONPOLAR MOLECULE -The shape of the molecule is symmetrical

  • Equal sharing of electrons
  • No dipole moment
  • Valence electrons are shared equally
• POLARITY BASED ON STRUCTURES

  POLAR MOLECULE - The shape of the molecule is asymmetrical

  • Unequal sharing of electrons
  • Has dipole moment
• AICPA (1941) - defined accounting as "the art of recording, classifying, and summarizing in a significant manner and in terms of money, transactions and events which are, in part at least, of a financial character, and interpreting the results thereof."