Chem

• Sig fig rules:

  • Any digit that is not a 0 is always significant
  • 0's between sig figs are significant
  • 0's to left of first non zero are not significant
  • If a number is grater than one, all 0's to the right of the decimal are significant
  • Exact numbers have infinite sig figs
• Multiplication sig figs- solution has the number of sig figs equal to the fewest sig figs in the factor
• Log sig figs- only digits in the mantissa (after decimal) are significant
• Atomic number= number of electrons and number of protons
• Atomic mass= Protons + neutrons
• Number of neutrons= atomic mass- atomic number
• Zeff- the nuclear charge an electron actually experiences, wth shielding taken into account
• Electrons closer to nucleus= takes more energy to remove and more shielded
• Electrons further from nucleus= lower Zeff
• Orbital filling order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p...
• Atomic size: Decreases L to R; Increases top to bottom
• Ionization energy: Decreases down group; Increases across period
• First ionization: first electron remove. Second ionization requires more energy
• Ionic bonding- metal+ nonmetal
• Covalent bonding- nonmetal + nonmetal
• Metallic bonding- electron sea
• Limiting reagent- the first reagent to be used up in a reaction.
• Linear (180 degrees)- 2 groups, 0 lone pairs
• Trigonal planar (120 degrees)- 3 groups, 0 lone pairs
• Bent (120 degrees)- 3 groups, 1 lone pair
• trigonal pyramidal- 4 groups, 1 lone pair
• trigonal bipyramidal (120, 90 degrees)- 5 groups, 0 lone pairs
• See saw - 5 groups, 1 lone pair
• T shape (90 degrees)- 5 groups, 2 lone pairs
• Oxidation- loss of electrons
• Reduction- gain of electrons
• Ideal gas law: PV = nRT
• Intermolecular forces- weak force of attraction between molecules with partial charges
• Ion- dipole forces= ion and nearby polar molecule attract each other

  • ex.) water and ionic compound
• Dipole-diploe forces= force between polar molecules that have a dipole moment
• Hydrogen bonding- hydorgen atom bonded to oxygen, nitrogen, or fluorine
• Dispersion forces- dipole in one molecule causes dipole in another; exists between all particles
• Molarity (M):

  M= mol/L
• Qc= Kp=concentration of products/ concentration of reactants
• More protons= smaller size
• Electronegativity= increases left to right
• oxygen oxidation state= always -2
• Elemental form oxidation= always 0