Unit 1

• There are two main groups of cells Prokaryotic and Eukaryotic
• Prokaryotic cells are found in two groups of single-celled organisms called bacteria and Archaea
• Eukaryotic cells contain membrane enclosed organelles
• Prokaryotic cells lack a nucleus and other membrane enclosed organelles
• A compound is made up of atoms joined by bonds
• The atomic number (# of protons) determines an atoms identity
• An atoms electron distribution determines its ability to form bonds
• An element is a substance that cant be broken down into other substances by chemical reactions
• A compound is a substance containing two or more elements in a fixed ratio (ex H2O is in the ratio 2:1)
• Trace element: An element necessary for life but required in small amounts

  ex Iron (Fe); Iodine (I)
• Atoms are composed of subatomic particles

  • Protons (+)
  • Electrons (-)
  • Neutrons
• Neutrons and Protons make up the atomic nucleus
• Outside of the nucleus is electron clouds or orbitals (probable location of electrons)
• Atomic Mass: Protons + Neutrons
• Isotopes

  • All atoms of an element have the same number of protons but may differ in the number of neutrons
  • Isotopes are two atoms of an element with different number of neutrons
  • Radioactive isotopes decay spontaneously, giving off particles of energy
• Valence electrons (outershell electrons) are most important in determining properties
• Covalent Bond: When electrons are shared between elements

  • Polar: shared unequally
  • Nonpolar: Shared equally
• In polar covalent bonds, electrons are shared unequally
• In nonpolar covalent bonds, electrons are shared equally
• Ionic Bond: When electrons are transferred between elements
• Electrons are found in different electron shells, each with a different distance from the nucleus (energy level)
• The closer to the nucleus, the less energy an electron has
• Covalent Bond: The sharing of a pair of valence electrons by two atoms
• Valence Electron: An outermost electron that is involved in bonding
• The chemical behavior of an atom is mostly determined by the number of valence electrons
• Electron Orbital

  • The probable location of an electron
  • Atoms interact in a way that completes their valence shells
• Atoms with incomplete valence shells can share(covalent) or transfer(ionic) valence electrons
• A molecule consists of two or more atoms held together by covalent bonds

  • A single covalent bond, or single bond, is the sharing of one pair of valence electrons
• Electronegativity is an atom's ability to attract electrons
• Ionic Bonds

  • When electrons are transferred between atoms
  • A positively charged Ion is a Cation
  • A negatively charged Ion is an Anion
  • Anions and Cations attract each other ----> Ionic Bond
• All chemical reactions are reversible
• Hydrocarbons: Organic molecules that consist of only hydrogen and carbon
• Hydrocarbons are a major component of petroleum
• Isomers

  • Compounds with the same molecular formula but different structure and therefore different properties
  • Three types of Isomers are Structural, Cis-trans, and Enantiomers
• Structural Isomers

  • Differ in the arrangement of covalent bonding partners
• Cis-trans Isomers

  • Differ in arrangement about a double bond.
  • X represents an atom or group of atoms attached to a double-bonded carbon
  • cis: The two x's on the same side
  • trans: the two x's on opposite sides

  
• Enantiomers are isomers that are mirror images of each other and that differ in shape due to the prescence of an asymmetric carbon
• Functional Groups: A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and involved in chemical reactions
• What is the chemical formula for the Hydroxyl Group?


  • OH
• What is the chemical formula for the Carboxyl Group?

  • COOH