# Chapter 7 Flashcards Preview

## CHM 115 Blechle > Chapter 7 > Flashcards

Flashcards in Chapter 7 Deck (125)
1
Q

Energy propagated by energetic and magnetic field that increases and then increases in intensity?

A

2
Q

A

by a wave model

3
Q

What is the wavelength?
What is it represented by?
What is it usually measured in?

A

distance between the crests of waves

ƛ

nm

4
Q

What is the frequency?
What is it represented by?
What is it usually measured in?

A

cycles per second

Greek letter nu (𝜈)

Hertz (Hz) [s^-1]

5
Q

Relationship between wavelength and frequency?

A

wavelength increases

frequency decreases

6
Q

When does the wavelength get more harmful?

A

the lower it is the more harmful

7
Q

What is the velocity?
What is it represented by?
What is it usually measured in?

A

distance a wave can travel per unit time

v

m/s

8
Q

What is the speed of light?

A

c = 3.00 x10^8 m/s

9
Q

What is the equation for velocity?

A

v = ƛ𝜈

10
Q

What is the amplitude?
What is it represented by?
What is it usually measured in?

A

height of crests, depth of troughs

A?

meters

11
Q

What is amplitude related to?

A

intensity

12
Q

What is the relationship between amplitude and intensity/

A

Amplitude increase, then Intensity increase

13
Q

What does intensity depend on?

A

different colors

14
Q

What causes a change in amplitude?

A

change in intensity

15
Q

What is an example of refraction?

A

rainbows

16
Q

What is an example of diffraction?

A

awarenesses that a flashlight is on

17
Q

Waves travel at different speeds through different media, the transition causes a change in direction?

A

refraction

18
Q

Does matter refract or diffract like energy does?

A

no

19
Q

Waves bend around the edges of an object?

A

diffraction

20
Q

A

an object emitting light when it is heated

21
Q

As heat is increased to an object, what happens/

A

the light changes color

22
Q

What relation does the blackbody radiation show/

A

relationship between heat & light intensity/wavelength (ƛ)

23
Q

Who takes the first steps of quantum theory and what did he say?

A

max planck

objects emit only certain quantities of energy

24
Q

What equation did plank come up with?

A

E = nh𝜈

25
Q

What does each letter stand for in the equation E = nh𝜈 ?

A

n = the quantum number (positive integer)

h = planks constant

𝜈 = frequency

26
Q

What is planks contant?

A

h = 6.626 x10^-34 J x s

27
Q

What are four major points of planck reasoning?

A
1. objects emit certain quantities of energy
2. energy must be emitted by atoms
3. atoms must only have certain quantity of energy available to it
4. an atoms energy must be quantized
28
Q

What does quantized mean/

A

occurring in fixed quantities

29
Q

When does an atoms energy change?

A

when it emits or absorbs a quantum

30
Q

What is the equation for ΔE ?

A

ΔE = Δ energy absorbed/emitted

ΔE = Δnh𝜈

31
Q

What is the formula for the smallest possible change in energy?

A

ΔE = h𝜈

32
Q

When monochromic light (single wavelength) of a sufficient frequency strikes a metal plate, a current flows with out a time lag?

A

the photoelectric effect

33
Q

With the photoelectric effect, for current to flow what must occur?

A

sufficient frequency

no time lag

34
Q

What does the threshold frequency change with?

A

different metals

35
Q

What is the minimum frequency of light a current requires called?

A

threshold frequency

36
Q

What does the classical model of light associate energy with?

A

associates energy with amplitude instead of frequency

37
Q

What is the no time lag?

A

the current flows the moment the light strikes the metal surface

38
Q

What did Albert Einstein say about light and energy?

A

light is quantized into bundles of energy

39
Q

What are the bundles of energy light is quantized into called?

A

photons

40
Q

What happens to photons when energy changes?

A

a photon is absorbed or emitted

41
Q

What is the E of a photon?

Who said this?

A

E (photon) = h𝜈 = ΔE (atom)

Albert Einstein

42
Q

What is the energy of atoms and photons related to and not related to?

A

related to frequency

not to amplitude

43
Q

How can an electron not be ejected from the metal by ?

A

by storying energy from multiple photons

44
Q

What is the relationship between wavelength and energy?

A

wavelength decreases, then

energy increases

45
Q

Scientists saw unique lines across other sections of the electromagnetic spectrum….Who came up with an equation for it?

A

Johannes Rydberg

1888

46
Q

What was Rydberg’s equations?

What elements did it work for?

A

(1/ƛ) = R(H) [(1/n2a) - (1/n2b)]

only H

47
Q

In Rydberg’s equation what must n be?

A

n must be an integer

n(a) < n(b)

48
Q

What is R(H)?

A

Rydberg’s constant for H

R(H) = 1.096776 x10^7 m^-1

49
Q

A

Niels Bohr

1915

50
Q

What was the Bohr model combined ideas of?

A

planck, einstein, and rydberg

51
Q

What is the ΔE ?

A

E final - E initial

52
Q

What does the Bohr model perfectly define but nothing else?

A

Hydrogen

53
Q

What are the 3 ideas of the Bohr model?

A
1. H only has stationary states: only certain energy levels
Each state associated with a fixed circular electron orbit around nucleus.
Higher energy level = Farther from nucleus
2. Atom in stationary state = no energy radiated
Atom doesn’t not change energy within orbit.
3. Electron moving to another orbit / atom changing energy state only occurs by absorbing/emitting a photon
54
Q

What are the five features of the Bohr model?

A
1. quantum numbers and electron orbit
2. ground state
3. excited state
4. absorption
5. emission
55
Q

The number that describes the state of an atom?

A

quantum number

56
Q

Distribution of e- that puts an atom at its lowest energy ?

A

ground state

57
Q

Distribution where 1 or more electrons move into a higher state so its not at its lowest energy?

A

excited state

58
Q

What does the Bohr model only predict?

A

the line spectra for only H atom

- b/c its a one electron model

59
Q

What is another issue with the Bohr model other than only working for H?

A

electrons do not move in fixed orbitals

60
Q

What do we still use today from the Bohr model?

A

idea of discrete energy levels

ground state / excited state terms

energy change is related to absorption/emission of specific photon energies

61
Q

What is a positive change in energy?

A

going from lower energy state to higher

an atom is absorbing a photon

62
Q

What is a negative change in energy?

A

going from lower energy state to higher

an atom is emitting a photon

63
Q

What did Bohr do and not have for his model?

A

fit theory to data
no basis for assumption

64
Q

Who studied fixed motion of a wavelength with a guitar string?

A

Louis de Broglie

65
Q

What was the big question that formed from Louis de Broglie’s research?

A

if energy can behave like particles,

why can matter not behave like a wave

66
Q

What is the formula for harmonics?

A

L = n (ƛ/2)

67
Q

What ideas does de Broglie use to form an equation?

What is the equation?

A

planck and einstein

ƛ = h / (m x u)

68
Q

What do these variables mean?
u =
v =
c =

A

speed of the electron
speed
speed of light

69
Q

What is one J ?

A

(1 kg x m^2) / s^2

70
Q

When will waves diffract around a slit or opening?

A

if the opening is on a similar scale to the wavelength of the light

71
Q

Who studied and made conclusion about x rays , wavelength, and crystalline materials?

A

Clinton Davisson
Lester Germer
1927

72
Q

What was said about the X-ray and wavelengths studied with crystalline?

x-ray wavelength
space between atoms in certain crystals
electron wavelength

What does this mean ?

A

x ray ƛ = 10^-10
crystals ƛ = 10^-10
electron ƛ = 7.27 x10^-10

electrons have a wavelength b/c diffracted

73
Q

What did Davisson and Germer see with the electron?

A

it made a pattern but not the same as the xray

** it has a wavelength

74
Q

What is momentum?

A

product of speed and mass

75
Q

the smaller the wavelength, the higher the ____and _____

A

energy

momentum

76
Q

What is the equation for momentum?

A

p = h/ƛ

77
Q

What happens when 2 things collide with different momentums/

A

they separate with the same momentums

* momentum is conserved

78
Q

What did Arthur Compton say?

A

1923

wavelength of light changes when its collided with an electron

79
Q

Who used theory to explain observation?

Who used observation to explain theory?

A

Planck, Einstein, and Bohr

Davisson, Germer, and Compton

80
Q

What exhibits both particle like and wavelike behavior/

A

matter and energy

81
Q

Who came up with the theory of relativity?

A

Albert einstein

1905

82
Q

What is the theory of relativity?

What is the equation?

A

matter and energy are alternate forms of the same entity

E=mc^2

83
Q

Who came up with he uncertainty principle?

A

Werner Heisenberg

1927

84
Q

What is the uncertainty principle ?

A

it is impossible to know with certainty both the location and the speed of an electron

85
Q

What is the formula for uncertainty?

A

(ΔX)(mΔu) ≥ (h)/(4𝞹)

Δ = uncertainty (not change)
^^^ eq says minimus amount error

86
Q

The Quantum Mechanics Atomic Model…

focuses on examining the ______ nature of objects on the atomic scale

describes an atom with specific quantities of _____ that result from allowed frequencies in an ____wave behavior

an electrons position can only be known with a certain probability

A

wave-like

energy
electron

87
Q

What did Schrödinger say about electrons and space near the nucleus?

A

the electrons matter-wave occupies space near the nucleus and is influenced by it

88
Q

What was Schrödinger equation ?

A

Erwin Schrödinger
*only need to understand

Ĥψ = Eψ

89
Q

What is Ĥ?
What is ψ?
What is E?

A

hamiltonian operator
wave function
total energy of the electron

90
Q

What does a wavefunction solution to the Schrödinger equation describe?

A

describes an orbital

91
Q

Each dependable wavelength with the Schrödinger equation depend on a series of variables called what?

A

quantum numbers

92
Q

What are the quantum numbers?

What do they describe?

A

n

mℓ

an atomic orbital

93
Q

What is the QN n?
What numbers are included?
What does it indicate?
a higher value = a ____ energy level

A

principle QN
positive integer (1, 2, 3…)
size
higher

94
Q

What is the QN ℓ?
What numbers are included?
What does it indicate?

A

angular momentum QN
integer from 0 to (n-1)
shape

95
Q

What is the QN mℓ?
What numbers are included?
What does it indicate?

A

magnetic QN
integer from -ℓ to +ℓ
orientation

96
Q

What do we use to describe energy states and orbitals?

A

wave function and the QN associated

97
Q

Describing a atom…

What is the n value?
What is the ℓ value?
What is the mℓ value?

A

shells

subshells

s: ℓ=0
p: ℓ=1
d: ℓ=2
f: ℓ=3

orbitals

98
Q

How are QN used to write and stuuufff?

A

nℓ (subscripted mℓ)

99
Q

What is the meaning?

ψ
ψ^2

A

no meaning

the probability density

100
Q

What does ψ^2 describe?

What can we turn it into?

A

the physical location that an electron can possibly occupy

a 3D shape

101
Q

What is the shape of the s orbital?

A

sphere

bigger n = bigger sphere
nodes (n-1)

102
Q

What is the shape of the p orbital?

A

Bean / Bowtie shape

bigger n = bigger sphere

3 p orbitals (x, y, and z)

103
Q

What is the shape of the d orbital?

A

butterfly

the fifth looks like a p orbital with a circle in the middle

104
Q

For the H atom…

___ is the only QN to impact the energy of the orbital
the energy of all four n=___ orbitals are equal
- 2s
- 2p(x)
- 2p(y)
- 2p(z)

*only for H

A

principle QN

n=2

105
Q

What can Schrödinger equation reveal?

• difficulties arise when there is ____
• the equation becomes___
• requires sophisticated _____
A

the total energy of an electron in an atom
more than one electron
unsolvable
approximations

106
Q

What were the additions to the quantum model?

A

another quantum number
limit to electrons in an orbital
splitting on energy levels

107
Q

What is that QN?
What numbers are included?
What does it indicate?

A

ms (s is subscript)
spin quantum number
2 possible: +1/2 , -1/2
the direction of spin

108
Q

What do all four QN describe together?

A

the spin and the orbital

109
Q

What did this person observe to form this principle?

A

Wolfgang
1925

excited states of helium

110
Q

What are the two main points of the exclusion principle?

A
1. no 2 electrons can have the same exact 4 QN’s in a single atom
2. an atomic orbital can only hold 2 electrons, each with opposite spins
111
Q

What is electrostatistics?

In H, all orbitals with an equal___ have equal ___
In other atoms, energy is based on what?

A

various effects of interacting charges cause a splitting of energy levels

n, energy
n and ℓ

112
Q

What is it called when electrons repulse each other counter acting nuclear charge?

A

shielding

113
Q

Is it easier to remove an electron with a more or less shielding?
why?

A

more

effective nuclear charge (Zeff) is reduced

114
Q

What is Zeff or effective nuclear charge?

What is nuclear charge?

A

what charge an atom feels

what charge is actually there

115
Q

Do higher or lower nuclear charges interact more strongly?

A

higher

116
Q

Nuclear charge…

a more positive nucleus creates a stronger attraction to the electron, which does what to the overall energy?

A

lowers the energy

117
Q

What are the two kinds of shielding ?

A
1. same energy level electrons
- multiple electrons decrease stability
2. electrons in inner energy levels
- inner electrons block those in outer levels
118
Q

What is electrical penetration?

what is it based on?

A

how close to nucleus

based on orbital shapes and radial probability
decreased ℓ = decreased E

119
Q

What is the nuclear charge and shielding for 2s?

A
```increased nuclear charge (over 2p)
decreased shielding (by 1s)```
120
Q

What causes there be general trends for sub levels?

A

shielding and penetration

121
Q

What happens to the shielding and penetration…when ℓ is smaller?

What is the sub shell order for energy?

A

greater penetrations
lower shielding

s < p < d < f

122
Q

What are two examples of quantum mechanics providing theoretical explanations for experimentally based periodic table?

A
1. electron assignments
- electron distributions in shells and sub shells
2. ground state electron configurations
- lowest energy distribution of electrons
123
Q

What is the Aufbau Principle?

A

Starting at the beginning of the periodic table…

add 1 electron to the next lowest energy sub shell for each atom.

124
Q

What are the two ways to represent the subshells using the Aufbau Principle ?

A
1. electron configuration
- shorthand designations for energy level
- nℓ^#
2. orbital diagram
- represents orbital and spin
- up and down arrow for spin
125
Q

What is the order you fill the sub shells?

A
```1s
2s
2p
3s
3p
4s
3d
4p
5s
4d
5p
6s
4f
5d
6p
7s
5f
6d
7p```