Org Chem

• Common Features of Organic Compounds:

  • Deals with carbon compounds
  • Have four bonds
  • Stable carbon is tetravalent
  • Other elements can be present called heteroatoms (e.g. N, O, S, P, and halogens)
  • Have chains of atoms and some compounds have rings
  • Combustible
  • Have low melting and boiling points
  • Less soluble in water
  • Several organic compounds may exist for a given formula, known as isomerism
  • Reactions of organic compounds are usually molecular rather than ionic, resulting in slow reactions
• Examples of Organic Compounds:

  1. Paper

  2. Nail Polish

  3. Candle

  4. Fabric

  5. Soap

  6. Gasoline
• Some Organic Compounds:

  1. Methane - CH4

  2. Ethanol - C2H6O

  3. Amoxicillin

  4. Fluoxetine

  5. Capsaicin
• Bonding:

  • Lewis Structures: Electron-dot structures
  • Kekule Structures: Line-bond structures
  • Skeletal Structures: Two-dimensional
• Charges of Atoms:

  • Atoms contain negatively charged electrons and positively charged protons; the number of each determines the atom's net charge
  • Formal Charge: The charge assigned to an atom in a molecule, assuming that electrons in all chemical bonds are shared equally between atoms
  • Oxidation Number: The number of charges an atom would have if the electrons were completely transferred to the more electronegative of the bonded atoms in a molecule (as if ionic bonding)
• Isomers:

  • Different molecules having the same molecular formula
  • Constitutional Isomers: Have the same molecular formula, but the connectivity of their atoms is different
  • Resonance: Two Lewis structures having the same placement of atoms but a different arrangement of electrons
  • Resonance Hybrid: The hybrid shows characteristics of both resonance structures, with the true structure being a composite of both resonance forms
  • Resonance Stabilized: Resonance allows certain electron pairs to be delocalized over two or more atoms, adding stability
• Atom:

  • Nucleus: Protons are positively charged, neutrons are neutral
  • Electrons are extremely small negatively charged particles that form an electron cloud orbiting the nucleus
  • Neutral Atom: Protons = Electrons
  • Atomic Number: Number of protons
  • Charged Atom: Cation (Protons > Electrons), Anion (Protons < Electrons)
  • Atomic Numbers: Number of protons
  • Mass Numbers: Number of protons + neutrons
  • Isotopes: Atoms with identical atomic numbers but different mass numbers
• Periodic Table:

  • Tabular display of the chemical elements
  • Group: Elements in the same column have similar electronic and chemical properties
  • Period: Elements in the same row are similar in size
  • Shell: Energy level
  • Subshell: Area in which electrons move within a shell (s, p, d, f)
  • Orbital: Orientation in space
  • S Orbital: Sphere of electron density, lower in energy than other orbitals of the same shell
  • P Orbital: Dumbbell shape of electron density, higher in energy than an s orbital in the same shell
• The First Row:

  • Formed by adding electrons to the first shell of orbitals around the nucleus
  • Contains only one orbital, the 1s orbital
• The Second Row:

  • Has a filled first shell of electrons with a 1s2 configuration
  • Contains one 2s orbital and three 2p orbitals
  • Each of the four orbitals in the second shell can hold two electrons, with a maximum capacity of eight electrons
• Bonding:

  • Leads to lowered energy and increased stability
  • Atoms gain, lose, or share electrons to attain the electronic configuration of the noble gas closest to them in the periodic table
  • Ionic Bond: Elements on the left side combine with the right side of the periodic table through the transfer of electrons
  • Covalent Bond: Elements like carbon in the middle of the periodic table share electrons
• Lewis Structures and Isomers:

  • Formal Charges
  • Basic Principles of Resonance Theory
  • Drawing Resonance Structures:
  • Two resonance structures differ in the position of multiple bonds and nonbonded electrons, while the placement of atoms and single bonds remains the same
  • Two resonance structures must have the same number of unpaired electrons
  • Resonance structures must be valid Lewis structures
• Resonance Hybrid:

  • A "better" resonance structure has more bonds and fewer charges
• Skeletal Structures with charged atoms