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exam 1 Flashcards

1
Q

Na atomic number, electron configuration

A

11p, 11n, 11e, 1s2 2s2 3p6 3s1

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2
Q

Na+ atomic #, electron config

A

11p, 11n, 10e, 1s2 2s2 2p6

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3
Q

one orbital in…

A

first shell

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4
Q

max of electrons in first row of elements’ orbital?

A

2 electrons

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5
Q

VSEPR (valence shell electron pair theory) is

A

electrons repel each other

orbitals don’t repel each other (can’t be in same place as another orbital)

fill 1st orbital before moving to the next

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6
Q

bonding is…

A

the arrangement of two atoms in stable organization

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7
Q

through bonding, atoms attain..

A

a complete outer shell of valence electrons and lower energy configuration

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8
Q

ionic bonds come from the transfer of…

A

electrons from one element to another

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9
Q

covalent bonds result from…

A

sharing of electron b/w two nuclei

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10
Q

ionic bonds come from…

A

electrostatic attraction b/w two charged species

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11
Q

ionic stability relates to

A

noble gas configuration

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12
Q

coloumb’s law shows the…

A

energy release when salt is formed from ions

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13
Q

second row elements can’t have more than…

A

8 electrons around them

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14
Q

consequences for neutral molecules?

A

1) atoms with 1/2/3 valence electrons from 1/2/3 bonds in neutral molecules

2) atoms w/ 4+ valence electrons form enough bonds to make an octet

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15
Q

how to calculate predicted # of bonds?

A

8 - # of valence electrons

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16
Q

when second row elements form >4 bonds…

A

their octets consist of both bonding (shared electrons) and nonbonding (lone pairs) electrons

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17
Q

lewis structures use…

A

lines to represent covalent bonds (shared electrons) and dots to represent unshared electrons (lone pairs)

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18
Q

formal charges are (x) specific

A

atom

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19
Q

formal charges are…

A

the charge assigned to individual atoms in a lewis structure

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20
Q

formal charge =

A

of valence electrons - # of electrons an atom “owns”

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21
Q

number of electrons owned by an atom is determined…

A

by its number of bonds and lone pairs

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22
Q

an atom “owns” all of its…

A

unshared electrons and 1/2 of its shared electrons

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23
Q

FC =

A

valence - sticks - dots

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24
Q

lower energy means

A

more stability

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25
Q

free radicals are….

A

more reactive b/c they don’t have an octet (they violate the octet rule)

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26
Q

isomers have the same molecular…

A

formula but completely different structures aka constitutional isomers

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27
Q

bond length decreases…

A

across a row as atom size decreases

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28
Q

bond length increases…

A

down a column as atom size increases

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29
Q

force of atom is stronger when…

A

electrons are closer

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30
Q

smaller atoms have…

A

smaller covalent bonds

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31
Q

larger atoms have…

A

larger covalent bonds

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32
Q

bond angle determines…

A

shape around any atom bonded to two other atoms

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33
Q

group is either an atom or…

A

a lone pair of electrons

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34
Q

number of groups surrounding a particular atom is called

A

geometry

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35
Q

stable arrangement keeps groups…

A

far away –> VSEPR (valence shell electron pair repulsion theory)

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36
Q

two groups:

A

linear, 180 degrees

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37
Q

three groups:

A

trigonal planar, 120 degrees

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38
Q

four groups:

A

tetrahedral, 109.5 degrees

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39
Q

skeletal structures:

A
  • assume there’s a C atom at junction of any two lines/line
  • assume enough H around each C to make each C tetravalent
  • draw heteroatoms and H directly bonded to them
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40
Q

a heteroatom is an atom…

A

without hydrogen and carbons

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41
Q

sigma bonds form when…

A

1s orbital of 1 H overlapping with 1s orbital of another H atom

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42
Q

sigma bond concentrates…

A

electron density b/w 2 nuclei formed

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43
Q

sigma bond is…

A

cylindrically symmetrical

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44
Q

constructive interference has…

A

lower energy

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45
Q

destructive interference has…

A

higher energy

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46
Q

what is hybridization?

A

combination of 2+ atomic orbitals

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47
Q

larger lobe =

A

stronger bond

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48
Q

bond rotation occurs around…

A

central C-C sigma bond (no double or triple bonds)

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49
Q

C-H and C-C bonds are

A

sigma bonds

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50
Q

overlap of 2p orbitals =

A

2nd C-C bond (more likely to break)

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51
Q

polarity of molecules

A

determines if molecule has a net dipole

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52
Q

polar molecule has one…

A

polar bond or 2+ bond dipoles that reinforce each other

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53
Q

coulomb’s law shows…

A

relation b/w force and energy of charged species (ions) with distance

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54
Q

same charge ions have…

A

+ delta E (bad)

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55
Q

ions of opp signs have

A

negative delta E (good)

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56
Q

closer ions =

A

stronger effect

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57
Q

lots of phenomena occurs to…

A

get low E

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58
Q
A
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59
Q

major elements?

A

C, N, O, H

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60
Q

minor elements?

A

halogens (F, Cl, Br, I), S, P, Si, metals

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61
Q

what is an atom?

A

building block of matter

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62
Q

what is a bond?

A

a stable joining of two atoms (via 2 electrons)

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63
Q

what is atomic mass?

A

average of all isotopes based on population

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64
Q

elements in the same row are roughly…

A

the same size

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65
Q

left to right means

A

elements get smaller in size

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66
Q

elements in the same column have roughly…

A

the same reactivity

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67
Q

as row number increases,

A

element rarity increases

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68
Q

chemical reactivity is based on

A

electrons in atomic orbitals

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69
Q

atomic orbitals are

A

locations where electrons can be found

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70
Q

orbitals can change shape but not…

A

number

i.e. an s and p orbitals can become 2 sp orbits (NOT 1 sp orbital)

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71
Q

shape of s orbital?

A

sphere

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72
Q

shape of p orbital?

A

dumbell

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73
Q

what is electron configuration?

A

arrangement of electrons in orbitals

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74
Q

shells are groups of orbitals…

A

increasing size and energy

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75
Q

group number tells you the number of…

A

outermost electrons

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76
Q

filled shells are thermodynamically…

A

favorable (noble gas configuration)

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77
Q

bonding allows completed…

A

outer shells / noble gas configuration (attempt to reach 8e- shells)

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78
Q

ionic bonding is

A

unshared electrons held together by strong electrostatic forces

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79
Q

covalent bonding

A

shared electrons

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80
Q

excess electrons manifest as…

A

nonbonding electron pairs

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81
Q

representation of molecules with electrons is called

A

lewis dot structures

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82
Q

lewis dot structures rules

A

1) draw only valence electrons around symbol
2) after that, give second row e- a full octet if possible
3) give each H 2e- if possible
4) may need to form double or triple bonds to 2nd row elements to form full octet

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83
Q

never draw 5 bonds around…

A

CARBON

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84
Q

how to calculate formal charge?

A

valence electrons - sticks - dots

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85
Q

what are isomers?

A

same elements, different connectivity/structure

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86
Q

constitutional isomers are

A

isomers with different connectivity

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87
Q

molecular geometry:

A

two groups (linear, 180 deg)
three groups (trigonal planar, 120 deg)
four groups (tetrahedral, 109.5 deg)

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88
Q

120 deg =

A

trigonal planar = flat

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89
Q

109.5 deg =

A

3D = tetrahedral

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90
Q

hybridized orbitals

A

atomic orbitals blend (mix) to become molecular orbitals

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91
Q

atomic orbitals overlap …

A

to form molecular orbitals

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92
Q

s can overlap with

A

sp, sp2, sp3 to form a sigma bond

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93
Q

p can overlap with

A

sp, sp2, sp3 to form a pi bond

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94
Q

s cannot overlap with

A

p

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95
Q

4 sigma bonds –>

A

sp3 (tetrahedral, 109.5)

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96
Q

3 sigma bonds are related to what hybridization?

A

sp2 (trigonal planar, 120)

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97
Q

2 sigma bonds

A

sp (linear, 180)

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98
Q

treat a lone pair like a

A

sigma bond

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99
Q

1 double bond implies

A

sp2 hybridization

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100
Q

1 triple bond implies

A

sp hybridization

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101
Q

pattern for carbon bonds:

A

increasing bond strength
decreasing bond length

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102
Q

sp3 bonds are longer than

A

sp2 bonds which are longer than sp

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103
Q

electronegativity is

A

an atom’s attraction for electrons in a bond

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104
Q

electronegativity increases

A

up and to the right of the periodic table

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105
Q

covalent bonds between atoms of different elements are not

A

equally shared

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106
Q

C-H bonds are not really polar covalent bonds because…

A

C and H have roughly the same polarity

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107
Q

polar molecules possess a

A

dipole (sum of polar forces of polar bond)

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108
Q

solubility of covalent molecule

A

polar solvent dissolve polar compounds and will NOT dissolve nonpolar compounds

109
Q

bronsted-lowry acid is a

A

proton (H+) donor

110
Q

bronsted-lowry base is a

A

proton (H+) acceptor

111
Q

acids often have a

A

+ or neutral charge

112
Q

bases often have a

A

negative or neutral charge

113
Q

bronsted lowry acid possesses what kind of proton?

A

donatable proton

114
Q

bronsted lowry base possesses a

A

lone electron pair or a pi bond

115
Q

is water a bronsted lowry acid or base?

A

depends on environment

116
Q

lewis acid is an electron pair acceptor or donor?

A

electron pair acceptor

117
Q

lewis base is an

A

electron pair donor

118
Q

is water a lewis acid or base?

A

depends on environment

119
Q

bronsted lowry acid base reactions involve the

A

transfer of a proton (normally must break a bond to form a bond)

120
Q

an acid that loses a proton

A

forms a weak conjugate base

121
Q

a base that gains a proton

A

forms a weak conjugate acid

122
Q

pka is

A

the quantitative measure of acid strength

123
Q

larger Ka =

A

more acidic something is

124
Q

small pka =

A

more acidic something is

125
Q

pka =

A

-log Ka

126
Q

pka is a pH but it is

A

the acid strength for an individual compound

pH is the acid strength of an environment (like a buffer solution)

127
Q

weak acid does not automatically mean

A

a strong base

128
Q

strong acids readily donate or accept protons?

A

donate protons

129
Q

do weak acids donate or accept protons?

A

donate protons

130
Q

predicting acid-base reactions:

A

reactions ALWAYS go strong to weak

131
Q

factors that affect acidity?

A

elemental

inductive effects (electronegativity)

resonance

hybridization (pi electrons)

132
Q

as you go right on the periodic table…

A

electronegativity increases, product stabilizes

133
Q

charges are stabilized when on

A

larger ions

134
Q

inductive effects signify the

A

presence of electronegative atoms increase acidity

135
Q

the more electronegative,

A

the more acidity

136
Q

the closer an electronegative atom is,

A

the more acidity

137
Q

hybridization effects state the more ‘s’ character

A

the more acidic

138
Q

more ‘s’ character, the more

A

(-) charge is held

139
Q

resonance structure are 2 (or more) lewis structures that

A

have the same placement of atoms but a different arrangement of pi electrons

140
Q

are resonance structures real?

A

they are model; reality is a hybrid of the structures

141
Q

rules of resonance #1

A

atoms and sigma bonds must stay in the same positions (pi bonds and lone pairs may vary in location)

142
Q

rules of resonance #2

A

two resonance must have same number of unpaired electrons

143
Q

rules of resonance #3

A

resonance structures must be valid lewis structures

144
Q

predicting resonance structures:

A
  • use curved arrows to ‘shift’ pi bonds or lone pairs
  • leave all sigma bonds alone
145
Q

electrons move to location where

A

room for electrons allows
- can only move 1 bond distance

146
Q

electrons can move

A

neg to neutral
neg to +
neutral to +

BUT NOT + to neutral/-

147
Q

resonance stabilizes

A

structures (makes them lower in energy)

148
Q

if you have resonance…

A

your structures are stable

149
Q

the higher the pka of the acid,

A

the stronger the resultant base

150
Q

lewis bases need

A

free pair of e- (lone pair or pi bond)

151
Q

lewis acids need room to accept

A

lone pairs (including breaking bonds)

152
Q

lewis acids are also known as

A

electrophiles

153
Q

lewis bases are also known as

A

nucleophiles

154
Q

curved arrows are used to indicate

A

movement of electrons

155
Q

an electron deficient carbon reacts with a

A

nucleophile (Nu-)

156
Q

electron rich carbon reacts with an

A

electrophile (E+)

157
Q

alkenes contain an electron rich double bond so they react with

A

electrophiles (E+)

158
Q

a lone pair on a heteroatom makes it

A

basic and nucleophilic

159
Q

pi bonds create (x) and are more…

A

nucleophilic sites, easily broken than sigma bonds

160
Q

alkanes are aliphatic hydrocarbons having

A

C–C and C–H sigma bonds

161
Q

acyclic alkanes have the molecular formula:

A

C n H 2n+2 where n = an integer
- contain only linear and branched chains of carbon atoms

162
Q

saturated hydrocarbons are

A

acyclic alkanes that have the max number of hydrogen atoms per carbon

163
Q

cycloalkanes contain

A

carbons joined in 1+ rings

164
Q

cycloalkanes’ general formula?

A

C n H 2n (have two fewer H atoms than an acyclic alkane with the same number of carbons)

165
Q

all C atoms in an alkane are surrounded by

A

four groups (making them sp3 hybridized and tetrahedral, bond angles are 109.5)

166
Q

butane and isobutane are…

A

constitutional isomers

same molecular formula, different arrangement

167
Q

constitutional isomers are

A

isomers that differ in the way the atoms are connected to each other
- they are two different compounds with the same molecular formula

168
Q

carbon atoms in alkanes are classified by….

A

the number of other carbons directly bonded to them

169
Q

primary carbon

A

carbon is bonded to one other C atom

170
Q

secondary carbon

A

carbon is bonded to two other C atoms

171
Q

tertiary carbon

A

carbon is bonded to three other C atoms

172
Q

quarternary carbon

A

carbon is bonded to four other C atoms

173
Q

hydrogen atoms are classified as

A

primary, secondary, tertiary

174
Q

primary hydrogen

A

H is on a C bonded to one other C atom

175
Q

secondary hydrogen

A

H is on a C bonded to two other C atoms

176
Q

tertiary hydrogen

A

H is on a C bonded to three other atoms

177
Q

CH4

A

1 C atom
n-alkane: methane

178
Q

C2H6

A

2 C ATOMS
ETHANE

179
Q

C3H8

A

3C
PROPANE

180
Q

C4H10

A

4C
BUTANE
2 CONST ISOMERS

181
Q

C5H12

A

5C
PENTANE
3 CONST ISOMERS

182
Q

C6H14

A

6C
HEXANE
5 CONST ISOMERS

183
Q

C7H16

A

7C
HEPTANE
9 CONST ISOMERS

184
Q

C8H18

A

8C
OCTANE
18 CONST ISOMERS

185
Q

C9H20

A

9C
NONANE
35 CONST ISOMERS

186
Q

C10H22

A

10C
DECANE
75 CONST ISOMERS

187
Q

C20H42

A

20C
EICOSANE
366,319 CONST ISOMERS

188
Q

cycloalkanes

A

molecular formula: C n H 2n
- contain carbon atoms arranged in a ring

189
Q

C3H6

A

cyclopropane

190
Q

cyclobutane

A

C4H8

191
Q

C5H10

A

cyclopentane

192
Q

cyclohexane

A

C6H12

193
Q

naming organic molecules

A

1) parent name (number of carbon in longest continuous chain)

2) suffix - func groups present

3) prefix tells: identity, location, number of substituents attached to the carbon chain

194
Q

prefix +

A

parent + suffix

195
Q

what is CH2 group commonly known as?

A

methylene

196
Q

what are alkyl groups?

A

carbon substituents bonded to a long carbon chain

197
Q

alkyl group is formed by

A

removing one H atom from an alkane

198
Q

how to name an alkyl group?

A

1) change –ane ending of parent alkane to —yl
2) thus methane (CH4) becomes methyl (CH3-) and ethane become ethyl

199
Q

if there are two chains of equal length..

A

pick the chain with more substituents

200
Q

number the atoms in the carbon chain to give the substituent the (x) number?

A

lowest

201
Q

if the first substituent is the same distance from both ends, number the chain to give….

A

the second substituent the lower number

202
Q

when numbering the carbon chain results in the same numbers from either end of the chain…

A

assign the lower number alphabetically to the first substituent

203
Q

substituents in a carbon chain get named as…

A

alkyl groups

204
Q

what is combined to create the IUPAC names of compounds/molecules?

A

combine substituent names and numbers + parent and suffix

205
Q

cycloalkanes are named using similar nomenclature rules but…

A

the prefix cyclo- immediately precedes the name of the parent

206
Q

naming cycloalkanes:

A

1) find the parent cycloalkane
2) name/number the substituents (no number is needed to indicate the location of a single substituent)
3)

207
Q

for rings with more than one substituent..

A

begin numbering at 1 substituent and proceed around the ring to give the second substituent the lowest number

208
Q

numbering the ring with two different substituents consists of…

A

numbering the ring to assign the lower number to the substituents alphabetically

209
Q

special case of an alkane composed of both a ring and a long chain…

A

if the number of carbons in the ring is greater than or equal to the number of carbons in the longest chain –> CYCLOALKANE

210
Q

do alkanes have high or low boiling points?

A

LOW

211
Q

boiling point (x) as the number of carbons (y)

A

increases, increases b/c of increasing surface area

212
Q

the boiling point of isomers decreases with branching because of…

A

decreased surface area

213
Q

alkanes have low…

A

melting points (compared to more polar compounds of comparable size)

214
Q

melting point increases as the number of…

A

carbons increases (b/c of increased surface area)

215
Q

melting point increases with…

A

increased symmetry

216
Q

solubility of alkanes?

A

alkanes are soluble in organic solvents and water

217
Q

conformations are…

A

different arrangements of atoms that are interconverted by rotation about single bonds

218
Q

when naming acyclic alkanes…

A

names are given to two different conformations

219
Q

eclipsed conformation:

A

C–H bonds on one carbon are directly aligned with the C–H bonds on the adjacent carbon

220
Q

staggered conformation:

A

C–H bonds on one carbon bisect the H–C–H bond angle on the adjacent carbon

221
Q

on the eclipsed conformation…

A

the C–H bonds are all aligned

222
Q

on the staggered conformation:

A

the C–H bonds in front bisect the H–C–H bond angles in the back

223
Q

what can convert an eclipsed conformation into a staggered one?

A

rotating atoms on one carbon by 60 degrees

224
Q

dihedral angle

A

angle that separates a bond on one atom from a bond on an adjacent atom

225
Q

newman projection:

A

end-on representations for conformations

226
Q

staggered conformations are more…

A

stable (lower in E) than eclipsed conformations

227
Q

electron-electron repulsion b/w bonds in the eclipsed conformation…

A

increases its energy compared with the staggered conformation (where bonding electrons are farther apart)

228
Q

when C–H bonds are farther apart,

A

molecule is more stable

229
Q

torsional energy

A

energy difference between staggered and eclipsed conformers

230
Q

torsional strain

A

increase in E caused by eclipsing interactions

231
Q

an energy min and max occur every

A

60 degrees as the conformation changes from staggered to eclipsed

232
Q

staggered conformation with two larger groups 180 degrees from each other is…

A

ANTI

233
Q

staggered conformation with two larger group 60 degrees from each other is…

A

GAUCHE

234
Q

which are lower in E: staggered or eclipsed?

A

staggered

235
Q

relative energies of the individual staggered conformations

A

depend on their steric strain

236
Q

what is steric strain?

A

increase in E resulting when atoms are forced too close to one another

237
Q

are gauche or anti conformations higher in E?

A

gauche, because of steric strain

238
Q

what is barrier to rotation?

A

energy difference b/w the lowest and highest energy conformations

239
Q

lowest energy conformation has all bonds….

A

staggered and all large groups anti
- alkanes are often drawn in zigzag skeletal structures to indicate this

240
Q

angle strain is…

A

the increase of energy when bond angles deviate from the optimum tetrahedral angle of 109.5 degrees

241
Q

cycloalkanes with more than three C atoms in the ring are…

A

puckered to reduce strain

242
Q

chair conformation is stable or unstable?

A

STABLE

243
Q

chair conformation is so stable because it…

A

eliminates angle strain (all C–C–C angles are 109.5) and torsional strain (all Hs on adjacent C atoms are staggered)

244
Q

axial hydrogens are located…

A

above and below the ring along a perpendicular axis

245
Q

equatorial hydrogens are located…

A

in the plane of the ring around the equator

246
Q

ring-flipping is an

A

important conformational change in cyclohexane

247
Q

in a ring flip, what changes?

A

axial H –> equatorial H
equatorial H –> axial H
up to down carbons
down to up carbons

248
Q

boat conformation is destabilized by…

A

torsional strain b/c the hydrogens on the four carbon atoms in the plane are eclipsed

249
Q

chair forms are (x) more stable than boat forms

A

7 cal/mol

250
Q

the equatorial position has more…

A

room than the axial position (larger substituents are more stable in the equatorial position)

251
Q

larger axial substituents create…

A

destabilizing 1,3-diaxal interactions

252
Q

what destabilizes boat conformation?

A

torsional strain b/c Hs on 4 carbon atoms in plane are eclispd

253
Q

larger substituents are more stable in the…

A

equatorial positions

254
Q

stereoisomers are isomers that…

A

differ only in the way the atoms are oriented in space

255
Q

prefixes that are used to distinguish stereoisomers?

A

cis and trans

256
Q

cis isomers has two groups on the

A

same side of the ring

257
Q

trans isomers have two groups on….

A

opposite sides of the ring

258
Q

all disubstituted cycloalkanes with two groups bonded to…

A

different atoms have cis and trans isomers

259
Q

alkanes are the only family of organic molecules that have no…

A

functional group (they undergo very few reactions)

260
Q

alkanes undergo…

A

combustion

261
Q

combustion is an…

A

oxidation-reduction rxn

262
Q

oxidation is the loss of

A

electrons

263
Q

reduction is the gain of

A

electrons

264
Q

to determine if an organic compound undergoes oxidation or reduction, we…

A

concentrate on the carbon atoms of the starting material and production

  • compare the relative number of C-H and C-Z bonds where Z = an element more electronegative than carbon (O, N, X)
265
Q

oxidation results in an increase of

A

C-Z bonds

266
Q

oxidation results in a decrease of

A

C-H bonds

267
Q

reduction results in a decrease of

A

C-Z bonds

268
Q

reduction results in an increase of

A

C-H bonds

269
Q

alkanes undergo combustion, meaning they

A

burn in the presence of oxygen to form CO2 and water

orgo (6 decks)

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