Exam 1 Flashcards
1
Q
commonly used prefixes in metric system
A
prefix symbol meaning power of 10
giga G 10^9
mega M 1,000,000 10^6
kilo k 1000 10^3
deci d 0.1 10^-1
centi c 0.01 10^-2
milli m 0.001 10^-3
micro μ 0.000001 10^-6
nano n 0.000000001 10^-9
pico p 10^-12
2
Q
rules for sig figs
A
1) all nonzero integers ALWAYS count for significance ex: 3456 has 4 sig figs
2) zeros (3 classes of zeros)
a) leading zeros:NEVER count as sig figs
ex: 0.048 has 2 sig figs
b) captive zeros: ALWAYS count as sig figs ex: 16.07 has 4 sig figs
c) trailing zeros: only significant when # HAS A DECIMAL POINT
ex: 9.300 has 4 sig figs; 0.004020 has 4 sig figs; 150 has 2 sig figs
3
Q
given: CH2O
calculate the mass percent of C, H2, and O
A
CH2O = 30.026 (12.01 + 2(1.008) + 16.00) C = 12.01 / 30.026 x 100 = 39.9% H2 = 6.71% O = 53.3%
4
Q
Fe2O3 (s) + 3 CO (g) -> 2 Fe (s) + 3 CO2 (g)
1.00 kg Fe2O3
find g of Fe
A
699g Fe
5
Q
2 CH3CHO (l) + O2 (g) -> 2 HC2H3O2 (l)
- 20.0g CH3CHO
- 10.0g O2
- find g of HC2H3O2
- find amnt of excess left
A
- 3 g HC2H3O2
2. 73 g excess left
6
Q
which has a higher frequency, blue or red light?
A
blue
7
Q
units of frequency
A
Hz, s^-1, 1/s
8
Q
units of h (planck’s constant)
A
J x s
9
Q
units of wavelength
A
m
10
Q
given a wavelength of 671 nm. find the E of 1 photon of light
A
2.96 x 10^-19
11
Q
wave
A
a continuously repeating change in matter or in a physical field
- light is an electromagnetic wave
- can be characterized by its wavelength and frequency
12
Q
wavelength
A
λ (lambda); the distance between any 2 identical points on adjacent waves
13
Q
frequency
A
ν (nu); the # of wavelengths that pass a fixed pt in one unit of time (s).
- unit: Hertz (Hz); 1/s; s^-1
14
Q
wavelength and frequency are related by the __
A
wave speed (c)
15
Q
equation of speed of light
A
c = νλ c = speed (m/s) λ = wavelength (m) ν = frequency (1/s)
16
Q
the speed of light equation is
A
inversely proportional
17
Q
given 742 nm. find ν
A
c = νλ *742 nm = 742 x 10^-9 m c = ν (742 x 10^-9 m ) (2.998 x 10^8 m/s) = ν (742 x 10^-9 m ) ν = (2.998 x 10^8 m/s) / (742 x 10^-9 m ) ν = 4.04 x 10^14 s
18
Q
what is the speed of light?
A
2.998 x 10^8 m/s
19
Q
the energy of each photon is __ to its frequency
A
proportional
20
Q
what is the electromagnetic spectrum?
A
gamma, x-rays, far UV, near UV, visible, near infrared, far infrared, microwaves, radar, radio waves (TV, FM, AM)
21
Q
what is the visible spectrum?
A
ROYGBV flipped
- blue has higher frequency than red
22
Q
waves can be __
A
diffracted
23
Q
Thomas Young
A
- British physicist
- showed light could be diffracted
- by 1900s, wave theory of light was established
- wave theory couldn’t explain the photoelectric effect
- diagram of current
24
Q
the photoelectric effect
A
- shouldn’t be a current cuz there’s an open circuit but there is
- e- attracted to (+) wire
- Einstein figured this out
- particle-wave duality
- ammeter measures current
- higher frequency = more energy
25
ammeter
measures current
26
Einstein proposed..
light consists of quanta/particles of EM energy called photons
E = hν
27
photon
package of light
28
what is Planck's constant?
6.626 x 10^-34 J x s
29
when photon has enough E, the e- will be __ from atom
ejected
30
given a wavelength of 742 nm, find the E.
2.68 x 10^-19 J
31
given a wavelength of 486 nm, find the E
4.09 x 10^-19 J
32
E = hν
```
E = energy (J)
h = planck's constant (6.626 x 10^-34 J x s)
ν = frequency (1/s)
```
33
light has properties of both __ and __
wave; matter
34
when a photon is absorbed, the e- is
ejected out
35
continuous spectrum
contains all wavelengths of light
36
line spectrum
shows only certain colors or specific wavelengths of light
- heated atoms emit light
* lines
37
atoms are
stable
38
energy-level postulate
- an e- can have only specific energy values called energy levels
- e levels are quantized
E = Rh / n^2
n= 1, 2, 3, ...∞
n = energy level/ principal quantum #
Rh = 2.179 x 10^-18 J (Rydberg constant)
39
going from n = 1 to n = 2, energy is
absorbed
40
going from n = 2 to n = 1, energy is
released
41
energy decreases as n __
increases
42
when n is 0, E is
∞
43
transitions between energy levels
- an e- can change e levels by absorbing e to move to a higher e level or by emitting e in the form of a photon to move to a lower e level
- for a H e-, the energy lost is given by:
∆E = Ef - Ei
44
light is __ by an atom when the e- transition is from lower n to a higher n ( nf > ni)
absorbed
| ∆E (+)
45
light is __ by an atom when the e- transition is from higher n to a lower n ( nf ≤ ni)
emitted
| ∆E (-)
46
Louis de Broglie
- French physicist
- reasoned that particles (matter) might have wave properties similar to light particles
- wavelength of a particle of mass (e-, p+, neutron), m (kg), and velocity, v (m/s), is given by the de Broglie rxn
47
de Broglie rxn
```
λ = h / mv
λ = wavelength (m)
h = planck's constant (J x s)
v = velocity (m/s)
```
48
calculate the wavelength of light emitted when e- in an H atom goes from n = 6 to n = 3
1.094 x 10^-6 m
49
Erwin Schrodinger
- invented quantum mechanics
- based off Broglie's work
- devised theory that could be used to explain the wave properties of e- in atoms and molecules
50
quantum mechanics
- mathematically describes the wave properties of submicroscopic particles
- uncertainty principle
- (∆x) (∆px) ≥ h / 4π
- ∆x: uncertainty of the x coordinate of the particle
- ∆px: uncertainty in the coordinate in the x direction
51
uncertainty principle
the product of the uncertainty in position and the uncertainty in momentum of a particle can be no smaller than Planck's constant divided by 4π
52
∆x
uncertainty of the x coordinate of the particle
53
∆px
uncertainty in the coordinate in the x direction
54
quantum mechanisms allows us to make..
statistical statements abt the regions in which we are most likely to find the e-
55
4 quantum #s
1) principal quantum number (n): energy level
2) angular momentum quantum number (l): shape of orbital
3) magnetic quantum number (ml): orientations
4) spin quantum number (ms): observing nature
- 1-3 define wave function of e-
- 4 defines magnetic property of e-
56
wave function for an e- in an atom is called an
atomic orbital
57
finding the angular momentum quantum number (l) for s, p, d, and f orbitals
s: l = 0
p: l = 1
d: l = 2
f: l = 3
58
angular momentum quantum number (l); L =
(n-1)
| * can have any integer value from 0 to n-1
59
the smaller the value of n, the __ the energy and sometimes the __ the orbital
lower; smaller
60
principal quantum # can have any
(+) value
61
orbitals w same value for n are said to be in the same __
shell
62
magnetic quantum number (ml)
- distinguishes orbitals of a given n and l
- for l = 0, ml = 0
- for l = 1, ml = -1, +1
- orbitals have same shape but diff orientations in space
63
spin quantum number (ms)
- 2 possible orientations of the spin axis of an e-
| - may have a value of either + 1/2 or - 1/2
64
shape of an s orbital
spherical
65
shape of a p orbital
2 lobes along straight line thru nucleus w one lobe on either side (kinda like a propeller)
66
shape of a d orbital
has a more complicated shape than an s or a p orbital
67
n
principal quantum number (energy level)
| 1,2,3,4,...
68
l
0, 1, 2,3, ...., (n-1)
69
ml
(-L, ... -1, 0, 1, ...+L)
70
ms
(+1/2, -1/2)
71
n = 1
l = 0, 1s
72
n = 2
```
l = 0, 2s
l = 1, 2p
```
73
n = 3
```
l = 0, 3s
l = 1, 3p
l = 2, 3d
```
74
s-subshell, ml =
0 (1 orbital)
75
p-subshell, ml =
-1, 0, +1 (3 orbitals)
76
d-subshell, ml =
-2, -1, 0, +1, +2 (5 orbitals)
77
e- configuration tree
```
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d 6f
7s 7p 7d 7f
```
78
e- configuration periodic table
```
period 1A: 1s
period 2A: 2s 2p
period 3A: 3s 3p
period 4A: 4s 3d 4p
period 5A: 5s 4d 5p
period 6A: 6s 5d 6p
period 7A: 7s 6d 7p
4f
5f
```
79
valence e-
outer e- involved in bonding rxns
80
valence configuration
just valence e-
81
s & p block
main group elements; valence is highest n subshell only
| *forget d-subshell
82
d block
transition metals; valence is ns & (n-1) d sub shells only
*include d-subshell
83
what is the valence configuration of B
2s2 2p1
84
what is the valence configuration of Al
3s2 3p1
85
what is the valence configuration of Ga
4s2 4p1
86
what is the valence configuration of Zn
4s2 3d10
87
what is the valence configuration of Mn
4s2 3d5
88
what is the valence configuration of K
4s1
89
what is the valence configuration of As
4s2 4p3
90
what is the valence configuration of Te
5s2 5p4
91
magnetic properties
- paramagnetic substance: weakly attracted; unpaired e-
| - diamagnetic substance: only paired e-
92
is group 1A paramagnetic or diamagnetic
paramagnetic
93
is group 2A paramagnetic or diamagnetic
diamagnetic
94
atomic radius
maximum in radial distribution function of outer shell
- down a group, atomic radius INCREASES
- across a period, atomic radius DECREASES
- e levels are concentric
- across a period, effective nuclear charge increases
95
effective nuclear charge
the (+) charge that e- experiences from nucleus
- equal to nuclear charge
- increases across period
- shell # is same across period
- size of outermost orbital and radius of atom decreases w/ increase of atomic #
- 1A is largest
- 8A is smallest
96
put the following elements in order of increasing atomic radius: Se, Ar, S
Ar, S, Se
97
1st Ionization Energy
minimum e needed to remove the highest/outermost e- from a neutral atom in the gaseous state
- bigger = easier to take e-
- atoms get smaller
- down a group, ionization e DECREASES
- across a period, ionization e INCREASES
98
2nd Ionization Energy is __ than the 1st Ionization Energy
larger
99
1/2 filled is more __ and means a __ ionization energy
stable; higher
100
when the 3rd ionization energy is dramatically higher, it means there are __ valence e-
2
101
electron affinity
e required to remove e- from atom's (-) ion
X + e- -> X-
X- -> X + e-
- 7A is highest, 6A, 4A, 1A, 5A,... lowest: 2A and 8A
102
building up principle
scheme used to reproduce the ground-state e- configurations by successfully filling sub shells w/e- in a specific order
- ground-state configurations determined by the total energies of the atoms
- ground state of atom obtained by filling orbitals of lowest e first
103
pauli exclusion principle
no 2 e- in 1 atom can have the same 4 quantum #s
104
what are the 3 physical properties of an atom?
1) atomic radius
2) ionization energy
3) electron affinity
105
metallic character
- elements w/ low ionization energies tend to be metals
| - those w/ high ionization energies tend to be non-metals
106
group 1A
ns1
107
group 2A
ns2
108
group 3A
ns2 np1
109
group 4A
ns2 np2
110
group 5A
ns2 np3
111
group 6A
ns2 np4
112
group 7A
ns2 np5
113
group 8A
ns2 np6
114
fixed charges
group 1 & 2; Al 3+, Ga 3+, Zn 2+, Cd 2+, Ag+
115
why is N more stable than O?
because half-filled orbitals in nitrogen's 2p orbital produce a more stable atom and a higher ionization energy
O: 2s2 2p4
N: 2s2 2p3
116
ground state
the lowest energy state available
117
excited state
higher energy level above ground state
118
pm to m
1 pm = 10^-12 m
119
GHz to Hz
x 10^9
120
exceptions to the ground state
Mo, Cr, Cu, Au, Ag
121
ground state
the lowest e configuration of an atom
| *5 exceptions
122
excited state
any other allowed configuration
- out of order
- each sub shell exists and can hold that # of e-
- not ground state, but is allowed
123
is 1s2 2s2 2p6 4s2 ground state or excited state?
excited bc it's out of order but is allowed and can hold that # of e-
124
not allowed (permitted)
sub shell doesn't exist (2d, 1p, 1d, 3f) and/or sub shell doesn't have that # of e- (s > 2, p > 6, d > 10)
125
valence configurations
1) main group ns np
| 2) transitions ns (n-1)d
126
l = 0
s subshell
| ml = 0
127
l = 1
p subshell
| ml = -1, 0, 1
128
l = 2
d subshell
| ml = -2, -1, 0, 1, 2
129
l = 3
f subshell
| ml = -3, -2, -1, 0, 1, 2, 3
130
E photon formula
|∆E electron|
131
what is the name of group 6A
chalcogens
