Units 1 & 2 Flashcards
(113 cards)
1
Q
What is electromagnetic radiation?
A
Radiant energy that exhibits wavelike behavior and travels through space at the speed of light in a vacuum.
2
Q
What is frequency?
A
Wave cycles per second.
3
Q
What is the ultraviolet catastrophe?
A
The contradiction between the classical model of blackbody radiation with experimental results in the early twentieth century; resolved by the Planck hypothesis.
4
Q
What is Planck’s constant?
A
A number used to calculate the radiant energy (E) absorbed or emitted by a body based on the frequency of radiation.
5
Q
What does quantized mean?
A
Having values restricted to whole-number multiples of a specific base value.
6
Q
What is a photon?
A
A particle of electromagnetic radiation with no mass that carries a quantum of energy.
7
Q
What is the photoelectric effect?
A
Refers to the emission of electrons from a metal when light shines on the metal.
8
Q
What is the dual nature of light?
A
The statement that light exhibits both wave and particulate properties.
9
Q
What is diffraction?
A
The bending of a wave as it moves around an obstacle or passes through a narrow opening.
10
Q
What is a diffraction pattern?
A
Bright spots and dark areas on a photographic plate.
11
Q
What is a continuous spectrum?
A
The uninterrupted broad band of all colors (wavelengths) emitted by incandescent solids.
12
Q
What is a line spectrum?
A
A spectrum showing only certain discrete wavelengths.
13
Q
Who is Maria Goeppert-Mayer?
A
German-born American theoretical physicist, and Nobel prize winner in Physics for proposing the nuclear shell model of the atomic nucleus.
14
Q
What is light?
A
- Pure kinetic energy
- no mass
15
Q
What is wavelength?
A
- Distance between peaks (or troughs) of a wave
- Measured in METERS
16
Q
What is frequency?
A
- Number of cycles that pass a point in one second
- Measured in HERTZ (Hz)
17
Q
What is the equation for the speed of light?
A
The speed of light (c), a constant, = wavelength x frequency.
18
Q
What is the electromagnetic spectrum?
A
The range of wavelengths or frequencies over which electromagnetic radiation extends.
19
Q
What are higher energy wavelengths?
A
Violet, blue, green.
20
Q
What are lower energy wavelengths?
A
Red, orange, yellow.
21
Q
What is blackbody radiation?
A
The electromagnetic radiation emitted from a heated solid.
22
Q
What does blackbody radiation depend on?
A
- The peak of emission wavelength AND intensity (amount of light) depend on the TEMPERATURE of the emitting body.
23
Q
What happens in blackbody radiation when wavelengths are very short?
A
Emission -> zero.
24
Q
What is Planck’s Law?
A
- Realized energy is not a continuous spectrum, but rather made of quantizable, discrete values.
- Led to Planck’s constant, defining changes in energy through frequency of light and INTEGER #s.
25
What is Planck's equation?
∆E = nhv
- n: integer number
- h: Planck's constant
- v: frequency
26
What is a photon?
- The quantity "hv"
- The unit (multiple) by which a system emits or absorbs energy.
27
What is energy measured in?
Joules.
## Footnote
Can only be emitted or absorbed in packets called photons.
28
What is the Bohr Model?
A model of the atom where electrons move rapidly around the nucleus in orbitals.
29
How are energy levels labeled in the Bohr Model?
Energy levels are labeled using the quantum number 'n', with n=1 being closest to the nucleus and having the lowest energy.
30
What happens at n = 7 in the Bohr Model?
At n = 7, it is the highest energy level, far enough away from the previous levels to be quantized.
31
What is the energy at n = infinity in the Bohr Model?
At n = infinity, the energy is 0J.
32
How do lines in the wavelength spectrum occur?
By the transition of an electron from one fixed orbit to another.
33
What is Bohr's equation for energy levels?
- En: energy of the nth level
- Z: atomic number (1 for H)
- n: integer quantum number for the orbit
- Works for any 1 electron atom!
34
What is special about the Hydrogen spectrum?
For hydrogen, almost all transitions ending in n=2 are in the visible region of the EM spectrum.
35
How to find out the ΔE for any 2 energy levels?
-2.178x10^-18 J (Z^2)(1/n^2final - 1/n^2initial)
- Z = atomic number
- n = integer
- Bohr Model
36
What are interference patterns?
- Constructive interference: waves match up, -> increased amplitude
- Destructive interference: waves don't match, -> decreased amplitude, can even get to 0.
37
What is the duality of matter?
The simultaneous behavior of electrons as a particle and as a wave.
38
What is the de Broglie wavelength?
The de Broglie equation depicts the relationship between a particle's mass and velocity and its dependence on wavelength.
39
What is the de Broglie wavelength equation?
wavelength=h/mv
- m: mass (kg)
- v: speed (m/s)
40
What is a standing wave?
A wave that appears to stand in one place, even though it is really two waves interfering as they pass through each other.
41
What are the rules about electrons as waves?
- Electrons can only have "standing wave" patterns of motion when subjected to a constraining potential.
- Their patterns can be represented with mathematical wavefunctions.
42
What does the Principal Quantum Number represent?
The level/shell that the electron exists in.
43
What is the mathematical symbol for the Principal Quantum Number?
n.
44
How does the Principal Quantum Number affect the size and energy of the orbital?
As n increases, the size and energy of the orbital also increase.
45
How is the number of nodes related to the Principal Quantum Number?
The number of nodes in an orbital is equal to n-1.
46
What are nodes in a wave function?
Points where the intensity of the wave function is 0.
47
What is the significance of nodes in an electron's wave function?
The electron will never be found there.
48
How do nodes appear visually in a wave function?
They look like little white rings or gaps.
49
What is the relationship between the number of nodes and the quantum number?
The number of nodes equals n-1.
50
What is the Angular Momentum Quantum Number symbol?
l.
51
What does the Angular Momentum Quantum Number determine?
Shape of orbital.
52
What are the possible values of the Angular Momentum Quantum Number?
0 to n-1
53
How do the values of the Angular Momentum Quantum Number match up with orbital letters?
l=0=s, l=1=p, l=2=d, l=3=f.
54
What are the shapes according to the Angular Momentum (l) values?
- l = 0, s orbital, spherical
- l = 1, p orbital, peanuts
- l = 2, d orbital, double dumbell
- l = 3, f orbitals, fuckery
55
What is the magnetic quantum number?
- m(l)
- Describes orientation of orbital.
- Ranges from -l to +l.
56
What are radial nodes?
- (n-l-1)
- Are spherical shells where the probability density is zero.
57
What are angular nodes?
- l
- Represented by planes where the probability densities are zero.
58
What is spin?
- s
- Describes electric field of electron.
- Spin up or spin down, +1/2 (up) or -1/2 (down).
59
What is the Pauli Exclusion Principle?
- An atomic orbital may describe at most two electrons, each with opposite spin direction.
- No two electrons can have the same set of quantum numbers.
60
What does degenerate mean?
Orbitals that are all in a single level; they have the same energy.
61
What is the order of energies of subshells within a shell?
s orbital < p orbital < d orbital < f orbital.
62
What is the Aufbau Principle?
In the ground state of an atom or ion, electrons fill the lowest energy orbitals first.
63
Where are the f orbitals located on the periodic table?
They go after the first 5d element and the first 6d element. So, 3 in on the bottom 2 rows of the PT.
64
What are core electrons vs valence electrons?
- Core: electrons in completely filled shells.
65
What is the ionization energy trend?
Increases up and to the right.
66
What is the atomic radius trend?
Increases down and to the left.
67
What is ionization energy?
- Amount of energy required to remove a valence electron from a GAS PHASE atom to make a GAS PHASE ion.
- Energy needed to remove an electron from each atom in exactly 1 MOL OF ATOMS.
68
What is the electron affinity trend?
Increases to the right and up.
69
What is an ionic compound also known as?
Salt.
70
What is electronegativity?
Ability of an atom to attract bonding electrons towards itself.
71
What is polarity?
A lack of electrical symmetry in a molecule. Charge differences on opposite ends of a structure.
72
What is a dipole moment?
- A measure of the separation and magnitude of the positive and negative charges in polar molecules.
- Arrow faces towards the more electronegative atom, the little plus sign faces towards the less electronegative atom.
73
What is ionic character?
Bonds with greater than 50% ionic character are considered ionic.
74
What are resonance structures?
- Lewis structures that have the same arrangement of atoms in a molecule but differ in the distribution of electrons among the atoms.
75
What are structural isomers?
- Have different covalent arrangements of their atoms.
- Use "formal charge" to determine the most likely structure.
76
What is a resonance hybrid?
The actual structure of a molecule that is intermediate between two or more resonance structures.
77
What must the sum of the formal charges for all atoms equal?
The overall charge on the species.
78
What are exceptions to the octet rule?
- Hydrogen (2)
- Beryllium (4)
- Boron (6)
79
Which atoms can do valence shell expansion?
Third-row elements.
80
What is electron domain geometry?
- The three-dimensional arrangement of the electron domains around an atom according to the VSEPR model.
81
What is molecular geometry?
The arrangement of bonded atoms.
82
What is the geometry for 2 electron domains?
Linear (180).
83
What is the geometry for 3 electron domains?
Trigonal planar (120).
84
What is the geometry for 4 electron domains?
Tetrahedral (109.5).
85
What is the geometry for 5 electron domains?
Trigonal bipyramidal (120 and 90).
86
What is the geometry for 6 electron domains?
Octahedral (90).
87
What is the shape for AX2?
Linear, linear, 180.
88
What is the shape for AX1E1?
Linear, linear.
89
What is the shape for AX3?
Trigonal planar, trigonal planar.
90
What is the shape for AX2E1?
Trigonal planar, bent.
91
What is the shape for AXE2?
Trigonal planar, linear.
92
What is the shape for AX4?
Tetrahedral, tetrahedral.
93
What is the shape for AX3E?
Tetrahedral, trigonal pyramidal.
94
What is the shape for AX2E2?
Tetrahedral, bent.
95
What is the shape for AXE3?
Tetrahedral, linear.
96
What is the shape for AX5?
Trigonal bipyramidal, trigonal bipyramidal.
97
What is the shape for AX4E?
Trigonal bipyramidal, seesaw.
98
What is the shape for AX3E2?
Trigonal bipyramidal, t-shaped.
99
What is the shape for AX2E3?
Trigonal bipyramidal, linear.
100
What is the shape for AXE4?
Trigonal bipyramidal, linear.
101
What is the shape for AX6?
Octahedral, octahedral.
102
What is the shape for AX5E?
Octahedral, square pyramidal.
103
What is the shape for AX4E2?
Octahedral, square planar.
104
What are the ideal bond angles for octahedral?
90*.
105
What are the ideal bond angles for trigonal bipyramidal?
90*, 120*.
106
What are the ideal bond angles for tetrahedral?
109.5*.
107
What are the ideal bond angles for trigonal planar?
120*.
108
What are the ideal bond angles for linear?
180*.
109
What shape is this?
Linear.
110
What shape is this?
Octahedral.
111
What shape is this?
Tetrahedral.
112
What shape is this?
Trigonal bipyramidal.
113
What shape is this?
Trigonal planar.
