quiz 1 Flashcards
what is the formal charge formal
FC= #valence e - 1/2 shared - unshared
When does a hydrogen have a neutral charge?
1 bond
when does a carbon have a neutral charge
4 bonds
when does a carbon become a carbocation
when it has 3 bonds
When is nitrogen neutral
3 bonds 1 lone pair
when does nitrogen have a +1
4 bonds
when is oxygen neutral
2 bonds 2 lone pairs (divalent)
when is oxygen +1
when it has 3 bonds and one lone pair
when is oxygen -1
when it has 1 bond and 3 lone pairs
what is the mass #
protons +neutrons
when are halogens neutral
with one bond and 3 lone pairs (monovalent)
what are atoms of the same element with different numbers of neutrons called?
isotopes
what is the mass # representative of?
the average masses of the naturally occurring isotopes
what is aufau principle?
what is poly exclusion principle?
what is hund’s rule?
- building up in orbitals (1s–> 2s—-2p—-)
- only two electrons per oribital with opposite spins
- if you have empty orbitals of same energy level, fill them with one e at a time with parallel spins
what are isomers
same molecular formula, different structure, different properties
what are resonance structures
electrons from π orbitals can shift, forming resonance structures of the same compound
what are the rules of resonance
- only real lewis structures
- hybrids are real, resonance structures are imaginary,
- only electrons move, not atoms
- the resonance hybrid is more stable
- a resonance structure is more stable with complete octets and delocalized charge
- resonance structures with the lowest FC’s are more stable
- more covalent bonds are lower in energy and more stable
carbon can be
electron rich or poor since it can be more or less electronegative than the atom its bonding to
what determines a bond’s polarity
unequal sharing on electrons
when is a structure tetrahedral
4 e groups, no lone pairs, 109.5
when is a structure linear
2 e groups, no lone pairs, 180
when is a structure trigonal planar
3 e groups, no lone pairs, 120
How do you identify the °Carbon?
1° Primary, 2° Secondary, 3° tertiary, 4° quaternary carbons are defined by the number of carbon atoms attached to the carbon analyzed
How do you identify the °carbo cation?
carbocations are defined by the number of carbons attached to the carbocation
How do you identify the °alcohol? or alkyl Halid
by the number of carbons attached to the carbon that the hydroxyl group is attached to
How do you identify the °amine/amide?
the number of carbons directly attached to the nitrogen
what makes a resonance structure more stable/ major contributing
- delocalization of charge
- lowest FC
- negative charge is on the most EN atom
- octet rule is fulfilled for the most amount of atoms
- highest # of covalent bonds
what are branched alkyl groups?
constitutional isomers of alkyl groups
whats the shortened name of isobutyl
i-Bu
whats the shortened name of sec butyl
sec-Bu
whats the shorted name of tert butyl
tert-bu
whats the shortened name of isopropyl
i-pr
what are the IMF’s by strength?
Ion-Ion, Dipole Dipole, H-Bonds, Dispersion Forces
What are ion ion forces
they are attractions between opposite charges
what are dip dip forces
interactions between dipoles
what is H bonding
interactions that occur when Hydrogen is bonded to an electronegative atom (FON)
what are dispersion forces
temporary distributions in partial charges that cause weak attractions
what causes a molecule with dispersion forces to have a higher boiling point?
increased surface area (straight chains > branched chains)
What is the stretch of a C=O bond
1700 cm^-1
what is the stretch of a C-H bond
2900 cm^-1
what is the stretch of a C(≡)C
2100 cm^-1
what is the stretch of O-H
3500 cm^-1
for a primary amine, how many peaks are possible? (NH2)
two, due to the symmetric and asymmetry bond stretches
for a secondary amine, how many peaks are possible? (NH)
one
what is a bronsted lowry acid
proton donor
what is a bronsted lowry base
proton acceptor
what is a lewis acid
e pair acceptor
what is a lewis base
e pair donor
a high Ka indicates what?
stronger acid
a low pka means what?
stronger acid
the strongest acid will have the
weakest base
