Question | Answer |
ammonium | NH4+ |
hydronium | H3O+ |
acetate | CH3COO- |
hydroxide | OH- |
chlorate | ClO3- |
perchlorate | ClO4- |
nitrate | NO3- |
permanganate | MnO4- |
carbonate | CO3 2- |
hydrogen carbonate | HCO3- |
dichromate | Cr2O7 2- |
phosphate | PO4 3- |
sulfate | SO4 2- |
empirical formula | defines the smallest whole number ratio of the atoms (usually ionic) |
molecular formula | accounts for all atoms present in the molecule (usually covalent) |
structural formula | shows atoms and bonding pattern |
diatomic molecules | hydrogen, nitrogen, oxygen, halogens |
1 mole | 6.022E10^23 things |
mass percent | the amount of mass each atom contributes to the total mass of the unit |
which atoms can have an expanded octet? | anything in period 3 or higher |
determining best Lewis structure (4) | -smaller formal charges
-fewer formal charges
-more negative charge for more electronegative atoms (v/v)
-*some believe the octet rule is always best |
formal charge | the charge on an atom based on the drawn Lewis structure
(# valence e's - assigned e's) |
electronegativity | the relative ability of a bonded atom to attract electrons (top right= highest) |
resonance structures | different ways of representing the same molecule w/ different bonding patterns |
electron delocalization | electrons delocalized due to different possible arrangements of single and double bonds |
bond order | (bonding pairs)/(positions) |
atoms that may have less than an octet | Be & B |
molecules that may have an unpaired electron | free radicals- NO, NO2 |
geometry & angle- 2 atoms around central | linear, 180 |
geometry & angle- 3 atoms around central | trigonal planar, 120 |
geometry & angle- 4 atoms around central | tetrahedral, 109.5 |
geometry & angle- 5 atoms around central | trigonal bipyramidal, 90 (axial) & 120 (equatorial) |
geometry & angle- 6 atoms around central | octahedral, 90 |
VSEPR | (valence shell electron pair repulsion)
electrons are located as far apart as possible to minimize repulsions |
2 outer atoms, 1 lone pair | bent, <120 |
3 outer atoms, 1 lone pair | trigonal pyramidal, <109.5 |
2 outer atoms, 2 lone pairs | bent, <109.5 |
4 outer atoms, 1 lone pair | seesaw, <90, <120
**equatorial position |
3 outer atoms, 2 lone pairs | t-shaped, <90
**equatorial position |
2 outer atoms, 3 lone pairs | linear, 180
**equatorial position |
5 outer atoms, 1 lone pair | square pyramid, <90 |
4 outer atoms, 2 lone pairs | square planar, 90 |
d hybrid orbital used | when there are <4 atoms around the central atom |
lone pairs & orbitals | paired in hybrid orbitals |
double bond type(s) | 1 pi bond, 1 sigma bond |
triple bond type(s) | 2 pi bonds, 1 sigma bond |
central atom w/ formal charge | add/subtract an electron |
sigma bonds | end-to-end overlaps of orbitals |
pi bonds | side-to-side overlaps of orbitals |