Module 1: Atoms Flashcards
(122 cards)
1
Q
Mass of a proton
A
1.673 e -27
2
Q
Mass of a neutron
A
1.675 e -27
3
Q
Mass of an electron
A
9.109 e -31
4
Q
1 Å = ???
A
1 Ångstrom = 1.0 e -10 m = 1.0 e -8 cm
5
Q
1 u = ???
A
1 amu = 1.6605 * 10 e -27 kg
6
Q
Charge of a proton
A
q p = 1.602 e -19 C
7
Q
Charge of an electron
A
q p = -1.602 e -19 C
8
Q
Coulomb’s law = ???
A
F = (1/4piE) (q1q2/r^2)
1 )(q1q2
(4pi*E)( r^2 )
9
Q
What is SIGMA? (E)
A
= 8.854 e -12 A*s/Vm
10
Q
JJ Thomson’s experiment, 1987
A
questioned current: negative charge and rays are the same (phosphor lit up when ray hit it, electrometer detected charge when ray hit it); can direct the ray with electricity and magnetism; electrons negatively charged; ratio of mass to charge of electrons
11
Q
Millikan’s oil-drop experiment?
A
floated charged oil droplets, with a calculated mass, to calculate the charge of the electron
12
Q
Rutherford’s gold foil experiment?
A
Shone alpha particles through thin gold foil: expected them to pass straight through the plum pudding: instead the bounced: nucleus!; estimated the radius of the gold nuclei
13
Q
What did J. J. Thomson discover?
A
Electrons are negatively charged. Ratio of electron charge over electron mass.
14
Q
What did Millikan discover?
A
Electron’s charge. Led to discovery of electron’s mass thanks to Thomson’s ratio.
15
Q
What did Rutherford discover?
A
The presence of the nucleus.
16
Q
Speed of light?
A
3 e 8 m/s
17
Q
Three important discoveries in the early 20t century
A
Atomic spectra, electron diffraction, the photoelectric effect
18
Q
Atomic spectra
A
Spectra of atoms show discrete absorption lines
19
Q
Electron diffraction
A
Particles (electrons) can also display interference, so there must be something about matter that enables it to act like light
20
Q
Interference
A
Property of electromagnetic waves (light)
21
Q
Photoelectric effect
A
Photons: cannot be split, specific momentum, behave like little packets of light, sort of like matter
22
Q
Quantum mechanics
A
The theory that governs the behavior and properties of small systems, like atoms and molecules
23
Q
Equation involving frequency, wavelength, velocity of light?
A
Velocity = frequency*wavelength
24
Q
Electromagnetic spectrum: left means what?
A
Long wavelength
Low frequency
Low quantum energy
25
Electromagnetic spectrum: right means what?
Short wavelength
High frequency
High quantum energy
26
Electromagnetic spectrum from left to right
AM radio waves, short wave radio, TV waves, FM radio, microwaves, radar, millimeter waves, telemetry, infrared, visible light from red to violet, UV, x-rays, gamma rays
27
Basic premise of quantum mechanics
Matter has wavelike properties
28
What do we see when we observe waves?
The intensity, which is the square of the amplitude
29
Way did deBroglie discover?
connection between the classical mechanics properties of a particle and its wave properties
30
What is the formula for particle momentum and wavelength?
P = h/^
Momentum (mass*velocity) = Planck's constant/ wavelength
31
Planck's constant?
6.626 e -34 J*s
32
How can we calculate the frequency of oscillations? Formula:
E = hv
Particle energy = Planck's constant*frequency
Particle energy is 0.5 mv^2 when dealing with kinetic energy
33
What is the quantization of energy?
Wave functions can only have certain shapes, so only certain energy values can occur, and energy exchange can only happen in specific step sizes
34
What experiment did Davisson and Germer conduct in 1927?
Electron diffraction: shone a ray at a crystal, only diffracted at certain allowed angles
35
Where does one do surface diffraction experiments?
In a vacuum because the surface needs to be very clean
36
How can me determine diffraction patterns?
Surface diffraction experiments, recording and graphing spatial patterns like n the helium beam experiment, and diffraction electron beams from molecules n a gaseous state, when they have any orientation and are depicted as circular rings
37
What is diffraction?
the bending, spreading and interference of waves when they pass by an obstruction or through a gap; occurs with any type of wave, including sound waves, water waves, electromagnetic waves such as light and radio waves, and matter displaying wave-like properties according to the wave-particle duality
38
How does one calculate the energy of ejected electrons?
E(kin) = hv - ø
Kinetic energy of ejected electron = Planck's constant * frequency - work function, which is a constant depending on the element
39
How much is one electron volt eV?
1.6 e -19 J
40
What is the fundamental quantity of quantum mechanics?
Psi, the wave function
41
What is psi wave function interpreted as?
Wave amplitude or probability amplitude
42
What is psi squared?
Probability density of finding a particle at a given point in space and time
43
Heisenberg uncertainty principle
One can know the position or momentum of a particle, but not both at the same time
44
Eigenstates
Wave functions that are solutions to the Schrödinger equation
45
Eigenvalues
Energies that are solutions to the Schrödinger equation
46
How do you figure out which state a wave function belongs to?
Count the nodes
47
What is the probability of finding a particle at the node of a wave equation for the Schrödinger equation?
Zero
48
Does the particle in the infinitely large box have to be in one of the plotted eigenstates?
No
49
Which is the simplest of all atoms?
Hydrogen
50
What is the name for the potential between the proton and electron when solving the Schrodinger equation for hydrogen?
Coulomb potential
51
What is the equation for the Coulomb potential?
```
V(r) = --Zq^2 / 4pi Eo r
z= nuclear charge, +1 for H atom
q= elementary charge, = 1.602 e -19 for a proton
r = distance of the electron from the nucleus
Eo = permittivity of vacuum constant, 8.854 e -12 C^2/JM
```
52
what does the wave function of the hydrogen atom describe?
the oscillatory motions of the electron
53
what is the name for the different wave forms that the electron can assume?
orbitals
54
what two factors determine the orbital?
the shape of the wave function and its associated energy
55
and orbital is what for electrons?
an "allowed place"
56
what are used to characterize orbitals?
"quantum numbers"
57
principal quantum number
n: [1, infinity) as integers
58
n
principal quantum number
59
angular momentum quantum number
l: zero and all positive integers up to n-1 [0, n-1]
60
name for orbital l=0
s orbital
61
name for orbital l=1
p orbital
62
name for orbital l=2
d orbital
63
name for orbital l=3
f orbital
64
s orbital
angular momentum l=0
65
p orbital
angular momentum l =1
66
d orbital
angular momentum l=2
67
f orbital
angular momentum l=3
68
magnetic quantum number
m: [-l, +l] integers: negative or positive integer between negative and positive "l," the angular momentum number
69
m
magnetic quantum number
70
what is an orbital with n=1 and l=0?
1s
71
what is the formula for writing orbitals?
nl = principal qn - angular momentum qn
72
what is the 2d orbital not allowed?
"d" signifies that the angular momentum qn "l" is 2. l"l must be less than or rqual to "n-1" in this case "2-1" = "1" and 2 is not less than or equal to 1
73
in hydrogen atoms, the energy depends only on what?
the principal quantum number
74
what is the name for the formula that describes the energy levels?
Rydberg formula
75
what is the rydberg formula and what does it describe?
the energy levels
En = (Z^2)(Qq4)(msube) / (8)(Eo^2)(n^2)(h^2)
me = mass of electron
n = princial qn
Z = nuclear charge, +1 for H-atom
q= eleemntary charge, 1.602e-19 C
Ec = permittivity of vacuum constant, 8.854e -12 C^2/Jm
76
what does the Rydberg formula allow us to calculate?
the energies of the allowed states in teh hydrogen atom
77
in the Rydberg formula, what does the energy approach as n approaches infinity?
zero
78
in the rydberg formula, energy approaches zero as n approaches what?
infinity
79
the energies of all finite n states are what?
negative
80
what does the lowest energy belong to?
the lowest n state, or n =1
81
what is the simplified formula for the energy level for a given principal qn of the hydrogen atom?
En = --2.18 e 18 J (1/n^2)
82
true or false: the energies of orbitals in atoms other than hydrogen can be approximated the the rydberg formula
false: complicated quantum mechanical calculations
83
spin quantum number
s: +1/2 or -1/2, up or down arrows
84
s
spin quantum number
85
what is the pauli exclusion principle?
one never finds the situation where two electrons have an identical set of 4 quantum numbers!
86
what is it called whe one never finds two electrons with the same four quantum numbers?
pauli exclusion principle
87
what are the general building rules for larger atoms?
use the hydrogen orbitals, no two electrons into the same oribtal, and Aufbau principle, Hund's rule
88
what is the aufbau principle?
start with orbitals of lower energy, then progress to higher energy
89
what is hund's rule?
maximize total spin:total spin should be as large as possible
90
what is the name for teh arrangement of the electrons in orbitals?
electron configuration
91
how many electrons fit in an s orbital?
2 (1 = 0, so m =0)
92
how many electrons fit in a p orbital?
6 (l = 1, so m = -1, 0, +1)
93
how many electrons fit in a d orbital?
10 (l = 2, so m = -2, -1, 0, +1, +2)
94
how many electrons fit in a f orbital?
14 (l = 3, so m = -3, -2, -1 0 +1, +2, +3)
95
what did the stern gerlach experiment discover?
electrons could only rotate about their axes two ways, leading to the spin atomic number only being -1/2 or +1/2
96
how many electrons fit in a p orbital?
6 (l = 1, so m = -1, 0, +1)
97
how many electrons fit in a d orbital?
10 (l = 2, so m = -2, -1, 0, +1, +2)
98
how many electrons fit in a f orbital?
14 (l = 3, so m = -3, -2, -1 0 +1, +2, +3)
99
in the periodic table, periods are what?
rows
100
what orbital is represented in period 1?
the n=1 orbital, because they have their outermost electrons in the n=1 shell
101
what orbital is represented in period 2?
the n = 2 orbital, because they have their outermost electrons in the n=2 shell
102
what does the listing by columns represent in the periodic table?
the orbital of the outermost electrons
103
why do 4s orbitals have lower energy that 3d?
the higher the n, the sublevel energies start to become closer together
104
why are there 10 transition elements?
the 3d atoms are used after the 4s orbital is full, and there are five d-orbitals that can hold 2 electrons each = 10
105
what does the listing by columns represent in the periodic table?
the orbital of the outermost electrons
106
what's an example of an ionization chemical reaction with sodium?
Na --> Na+ + e-- deltaE = IE = 8.26 e -19 J
107
how does one find the chemical atomic mass of an element?
take a weighted average with the exact mass of each isotope and its natural abundance
108
what is ionization energy (IE)?
the energy required to remove an electron from an atom
109
what's an example of an ionization chemical reaction with sodium?
Na --> Na+ + e-- deltaE = IE = 8.26 e -19 J
110
across a period from left to right, what happens to ionization energy?
increases (filling out the valence, more likely to add electrons instead of lose)
111
down a group from top to bottom, what happens to ionization energy?
decreases (larger atoms, so valence electrons further from nucleus and easier to lose and electron)
112
what is electron affinity (EA)?
the energy release when an electron attached to a neutral atom
113
what is an example of electron affinity with oxygen?
O + e-- --> O- delta E = -EA = -2.35e-19 J (negative means energy released)
114
across a period from left to right, what happens to electron affinity?
increase (want to collect the rest of the electrons to complete the valence)
115
what happens to the atomic radius as one puts electrons into higher orbitals?
atomic radius increases
116
what happens to atom size as the atoms contain more electrons?
radius increases because of more Coulomb repulsion between like-charged electrions
117
down a group from top to bottom, what happens to atomic radius?
increase: more Coulomb repulsion between more electrons, also more orbitals being filled
118
in general for size, higher period atoms are ____ than lower period atoms
larger
119
across a period from left to right except for noble gases, what happens to atomic radius?
decreases: nuclear charge is increasing as well as number of electrons increasing as well as increase in electrostatic attraction
120
down a group from top to bottom, what happens to atomic radius?
increase: more Coulumb repulsion between more electrons, also more orbitals being filled
121
in general cations are ____ than their neutral atom size
smaller: decreased electron electron reuplsion
122
in general anions are ___ than their neutral atom size
larger: increased electron electron repulsion
