3. Bonding, Structure & Energy Changes Flashcards
(117 cards)
1
Q
describe e-s in a covalent bond
A
shared between 2 atoms
attracted to both nuclei simultaneously
2
Q
describe e-s in a non polar bond
A
e- attracted to both nuclei same extent = forms symmetrical e- cloud
3
Q
between what molecules/atoms do non polar bonds form
A
betw non metal atoms of same kind
4
Q
describe e-s in a polar covalent bond
A
e shared unevenly between atoms
unsymmetrical e- cloud
5
Q
for a tetrahedral how many bonded and non bonded e- pairs are there and what is the angle
A
4 bond
0 lone
109.5*
6
Q
for a trigonal pyramid how many bonded and non bonded e- pairs are there and what is the angle
A
3 bond
1 lone
109.5*
7
Q
for a v shaped how many bonded and non bonded e- pairs are there and what is the angle
A
2 bond
2 lone
109.5
8
Q
for a trigonal planar how many bonded and non bonded e- pairs are there and what is the angle
A
3 bond
0 lone
120
9
Q
for a v shaped how many bonded and non bonded e- pairs are there and what is the angle
A
2 bond
1 lone
120
10
Q
for a linear how many bonded and non bonded e- pairs are there and what is the angle
A
2 bond
0 lone
180
11
Q
for a trigonal bipyramidal how many bonded and non bonded e- pairs are there and what is the angle
A
5 bond
0 lone
120 & 90
12
Q
for a distorted tetrahedron or seesaw how many bonded and non bonded e- pairs are there and what is the angle
A
4 bond
1 lone
120 & 90
13
Q
for a T shaped how many bonded and non bonded e- pairs are there and what is the angle
A
3 bond
2 lone
90
14
Q
for a octahedral how many bonded and non bonded e- pairs are there and what is the angle
A
6 bond
0 lone
90
15
Q
for a square pyramid how many bonded and non bonded e- pairs are there and what is the angle
A
5 bond
1 lone
90
16
Q
for a square planar how many bonded and non bonded e- pairs are there and what is the angle
A
4 bond
2 lone
90
17
Q
how many orbitals does s sub level have
A
1
18
Q
how many orbitals does p sub level have
A
3
19
Q
how many orbitals does d sub level have
A
5
20
Q
how many orbitals does f sub level have
A
7
21
Q
what is different about orbital levels for transitional elements
A
4s level overlaps between 3p and 3d levels
22
Q
1st energy level has how many orbitals and how are these arranged
A
1 orbital
1s
23
Q
2nd energy level has how many orbitals and how are these arranged
A
4 orbitals
2s + 3 x 2p
24
Q
3rd energy level has how many orbitals and how are these arranged
A
9 orbitals
3s + 3 x 3p + 5 x 3d
25
4th energy level has how many orbitals and how are these arranged
16 orbitals
4s + 3 x 4p + 5 x 4d + 7 x 4f
26
what is the periodic table trend for size of atoms across period from left to right
decrease radii
27
explain why the size of atoms decreases across period from left to right
e- add to same energy level and proton add to nucleus
leads to increase nuclear charge
increase attraction between valence e- and nucleus = e- pulled closer to nucleus
28
what is the periodic table trend for size of atoms down a group
increase radii
29
explain why the size of atoms increase down a group
valence e- in higher energy level so e- further from nucleus
increased nuclear charge cant overcome increased distance from nucleus
30
what is the periodic table trend for size of + ion compared to the atom
smaller radii than atom
31
explain why the size of + ion is smaller compared to the atom
e- loss = loss of complete energy level so outer e- closer to the nucleus
32
what is the periodic table trend for size of - ion compared to the atom
larger radii
33
explain why the size of - ion is larger compared to the atom
e- added to valence shell = increase repulsions between e-
34
what is the periodic table trend for ionization energy across period from left to right
increases
35
explain why the ionization energy increases across period from left to right
increased nuclear charge and same energy level filled with e- across period so increase attraction to nucleus and valence -
decrease atomic radii so harder to remove valence e-
36
what is the periodic table trend for ionization energy down a group
decreases
37
explain why the ionization energy decreases down a group
increased distance between nucleus and valence e-
decreases attraction so less energy to remove valence e-
valence e- also repelled by other e- so valence e- shielded from nuclear attraction
38
what is the periodic table trend for electronegativity across a period from left to right
increase
39
what is the periodic table trend for electronegativity down a group
decrease
40
explain why the electronegativity decreases down a group
valence e- further from nucleus and shield from other e-
decrease attraction of bonding e- and nucleus
41
explain why the electronegativity increases across a period from left to right
increase nuclear charge increases attractive nucleus and valence e-
increases attractive bond e- and nucleus
42
what forces hold together molecular substances
van der waals
43
what kind of dipoles are between non polar molecules and polar molecules respectively
betw non polar molecules = temporary diploe
betw polar molecules = permanent dipole
44
for molecular substances
what is the melt/boiling point relatively speaking and why
low
due to weak van der waal forces
45
for molecular substances
what is the electricity conduction and why
none
no charged particles
46
for molecular substances
what is the solubility in water and why
low
solvent water and solute intermolecular forces are of different magnitudes
47
for molecular substances
what is the solubility in non polar solvents and why
solube
same kind/strength of solvent and solute intermolecular forces
48
what are the 3 kinds of extended networks
ionic
covalent
metallic
49
for ionic substances what arrangement are the bonds in and what kind of bonds are present
arranged in lattice bond with strong ionic bond
50
for ionic substances
what is the melting/boiling points relatively speaking and why
high
strong ionic bonds
51
for ionic substances
what is the conductivity and why
conductive only in liquid state
freely moving ions in soln
52
for ionic substances
what is the solubility in polar solvents and why
soluble
solvent and solute attraction > attraction between ions
53
for ionic substances
what is the solubility in non polar solvents
not soluble
54
how would you describe ionic substances texture
brittle
hard and liable to breaking
55
what bonds are present in covalent substances
covalent bond
56
what is the bonding like in 2d networks like graphite
C bonded to 3 other C and 1 e- is delocalised which holds sheets together via temporary dipole
57
what is the bonding like in 3D networks like diamond
C bond to 4 other C
58
for covalent substances
what is the melting and boiling point relatively speaking and why
high
strong covalent bond
59
for covalent substances
what is the conductivity and why
dont conduct
no free moving charges except in graphite due to delocalised e-
60
for covalent substances
what is the solubility in all solvents
insoluble in all solvents
61
for 3d covalent substances
what is the texture/strength and why
very hard 3D networks like diamond
due to strong directional bond
62
what bonds and arrangement are present in metallic substances
atoms held in lattice structure via metallic bonds
metal atoms valence e- held loosely attracted to neighboring atoms nuclei = non directional
63
for metallic substances
what is the melting and boiling points relatively speaking
high
64
for metallic substances
what is the conductivity and why
conductors
moving valence e- form non directional bonding
65
for metallic substances
what is the solubility and why
insoluble in all solvents
66
for metallic substances
what is the density and why
high density
close packing
67
for metallic substances
what is the texture and why
malleable and ductile
due to non directional bonding
68
for metallic substances
what is the heat conductivity and why
good
atom vibrates and free e- transfer energy
69
what are the 3 intermolecular forces
temporary dipoles
permanent dipoles
Hydrogen bonds
70
what does a + enthalpy mean
energy is abosorbed
71
what does a - enthalpy mean
energy is released
72
what is the change in rH for exothermic reactions
negative
73
what is the change in rH for endothermic reactions and what does this relate to bonds
positive
bonds broken
74
what is the change in rH equation
change in rH = products - reactants
75
what is the change in rH for endothermic reactions and how does this relate to bonds
positive
bonds formed
76
what does a natural system tend towards for entropy
tends towards disorder
77
is increased disorder or entropy + or -
+S
78
what does a natural system tend towards for enthaply
tends towards decreased enthalpy (exothermic)
79
what is the equation for double bond equivalents
DBE = 1/2 (2nC + nN - NH + 2)
where:
nC = number of carbons
nN = number of nitrogens
nH = number of hydrogens
80
what are DBEs
number of rings or pi bonds present
81
what are the 3 types of conformational isomers
sawhorse projections
newman projections
cyclohexane conformers (chair and boat)
82
what are conformational isomers
what is the same and what is different
can it interconvert
same molecular formula and bonding sequence
different spatial arrangement
interconverts via rotation about single bond
83
what are the 2 types of sawhorse projections and how are they related
staggered and eclipsed
related by one 60* rotation
84
what is the most stable sawhorse projection
staggered = most stable
eclipsed = least stable
85
what are the newmans projections viewed along carbon wise
viewed along C2-3
86
how many newman projections are possible
4
87
what are the 2 types of staggered and eclipsed newmans projections possible
staggered - anti
eclipse
staggered - gauche
eclipse - syn
88
of the 4 newmans projections which are most and least stable
why is this
staggered - anti = most stable
eclipse
staggered - gauche
eclipse - syn = least stable
anti has largest groups greatest distance apart while syn has largest groups eclipsed
89
which of the two is always more stable
staggered is always more stable than eclipsed
90
what is the lowest energy conformation of a cyclohexane conformer
why
chair as its staggered
91
how are the Hs designated on chair and boat conformers
chair = axial (up and down) and equatorial (sideways)
boat = no axial or equatorial as both ends are pulled up
92
what is the highest energy conformation of a cyclohexane conformer
why
boat
as its eclipsing
93
when you do a ring flip for a chair conformer what happens to the axial and equatorial H
what doesnt change about the H
axial becomes equatorial and vice versa
up and down dont change
94
what do substituted cyclohexanes favor in terms of chair and boat conformers
favor conformation of chair that has largest atom in equatorial position
95
what are configurational isomers
what is the same and what is different
can it interconvert
same formula and bonding sequence
spatial arrangement differ
convert via break/reformation of covalent bond
96
what are the 2 types of configurational isomers
diastereomers
enantiomers
97
what are the 2 types of diastereomers
cis/trans
E/Z
98
what are E/Z used for
alkenes
99
what is the Cahn ingold rules of priority
H < C < N < O < F < Cl < Br < I
100
what are enantiomers
sp3 C with 4 different groups attached
chiral molecule
101
what is R and S for enantiomers
Clockwise decrease = R
anticlockwise decrease = S
102
what are meso compounds
mirror images but superimposable
103
what happens in chromatography
mixture is adsorbed on polar stationary phase and polar mobile phase passed over it
104
what does the polar solute do in chromatography in terms of what it is attracted to and its speed of movement
more attracted to polar stationary phase so moves more slowly
105
what does the non polar solute do in chromatography in terms of what it is attracted to and its speed of movement
less attracted to polar stationary phase so moves rapidly
106
what is homolytic cleavage
1 e- from bond ends up on each formerly bonded atom
107
what bonds is homolytic cleavage seen in
non polar bonds
108
what does homolytic cleavage produce
generates radicals
109
what are radicals
neutral species with unpaired e-
110
what is heterolytic cleavage
both e- of bond end up on one formerly bonded atom
e- always moves to electronegative atom
111
what does heterolytic cleavage produce
produces + and -
112
are carboanions or carbocations more common
carbocation
113
order the following in order of most to least stable carbocations
methy, 2*, 1*, 3*
most stable = 3* > 2* > 1* > methyl = least stable
114
what is the e- donor and acceptor in polar reactions
e- donor = nucleophile
e- acceptor = electrophile
115
what are non polar reactions
reactions of free radicals
116
what is Sn2 mechanism
bond break/make simultaneously in single step
117
what is Sn1 mechanism
bond break the form in 2 steps
1. heterolytic bond break forms reactive carbocation intermediate
2. polar bond forms between nucleophile and electrophile
3. heterolytic bond break forms neutral product
