Week 8 Flashcards

1
Q

constructive interference

A

occurs in regions where peaks or troughs for the 2 waves coincide

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2
Q

destructive interference

A

occurs in regions where the peak of one wave coincides with trough

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3
Q

amplitudes of interfering waves add together and produce a…

A

resultant wave

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4
Q

diffraction

A

wen a wave encounters an obstacle, the wave appears to bend around a small obstacle or spread out in semicircles

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5
Q

light shows properties of ____ and ____

A

particles- through photoelectric effect
waves- through light diffractions and interferences

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6
Q

energy levels of the hydrogen atom are given by equation

A

En= -2.179*10^-18(J/n^2)

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7
Q

De Broglie Wavelength (predicted that a particle with mass m and velocity v should also exhibit the behavior of a wave given by..)

A

wavelength=h/mv

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8
Q

wavefunction

A

mathematical description of an atomic orbital that describes the shape of the orbital, it can used to calculate the probability of finding the electron at any given location in the orbital as well as dynamical variables such as the energy and the angular momentum

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9
Q

interpretation of the wavefuntion

A

electrons are still particles, and so the wave represented by wavefunction variable aren’t physical waves, when you square them you obtain probability density which describes probability of the quantum particle being present near a certain location in space

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10
Q

wavefunction can be used to determine

A

the distribution of the electrons density with respect to the nucleus in an atom (but cannot be used to pinpoint exact location of the electron at any given time)

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11
Q

electrons can exists…

A

only on discrete energy levels but not in-between them, meaning the energy of an electron in an atom in quantized

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12
Q

principle quantum number variable

A

energy levels are labeled with an n value where n= 1 to infinity (energy levels of an atoms are greater with the greater value of n)

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13
Q

principle quantum number

A

defines the location of the energy level, similar concept as n in Bohr’s model of shell number the further from the nucleus the higher the shell number the higher the energy level

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14
Q

deltaE= Efinal-Einitial= -2.179*10^-18(1/nf^2 - 1/ni^2)

A

deltaE= Efinal-Einitial= -2.179*10^-18(1/nf^2 - 1/ni^2)

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15
Q

atomic orbital

A

a general region in an atom within which an electron is most probable to reside

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16
Q

angular momentum quantum number

A

(l) integer defines the shape of the orbital, l=0,1,2.. n-1 (if n=1 only one value of l=0; if n=2 whereas l=1, 0)

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17
Q

orbitals with the same value of l

A

will form a subshell

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18
Q

angular momentum is

A

a vector, electrons with this can have this momentum oriented in different directions

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19
Q

magnetic quantum number

A

(ml), specifies the z component of the angular momentum, the orbital orientation (-l to l, if l=1 ml= -1,0,1)

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20
Q

orbital abbreviations

A

l=0 s orbital
l=1 p orbital
l=2 d orbital
l=3 f orbital

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21
Q

orbitals

A

mathematically derived regions of space with different probabilities of electrons in them

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22
Q

interpretation of wavefunctions (orbitals)

A

probability density of finding an electron at a given point in space [wavefunction(r)]^2

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23
Q

dot density diagram

A

higher density of black dots, higher probability of finding electrons

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24
Q

radical probability

A

probability of finding a 1s electron at a distance r from the radius
-calc by adding probability of an electron being at all points ona series of x spherical shells of radius r1, r2, r3, rx-1, rx

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25
Q

electron probability density greatest at

A

r=0

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26
Q

surface area of each spherical is equal to

A

4(pi)r^2

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27
Q

boundary surface plot

A

spherical shaped plot constructed by drawing a circle or sphere around a large percentage (75-90ish) of the dots

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28
Q

s orbitals in n=2, 3… however look a little different

A

-the electron probability density doesn’t fall off smoothly with increasing r
-series of minima and maxima are observed (corresponds to radical nodes)

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29
Q

nodes

A

points with 0 amplitude
-number of radical nodes in an orbital is n-l-1

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30
Q

3 things happen to s orbitals as n increases

A
  1. they become larger extending farther from the nucleus
  2. they contain more nodes, similar to standing wave that has regions of significant amplitude separated by nodes
  3. for given atom, s orbitals also become higher in energy as n increases because of the increased distance from the nucleus
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31
Q

p orbital

A

-3D model with x, y and axis
-because 2p subshell has l=1, with ml(-1,0,1) there are 3 2p orbitals

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32
Q

only ___ orbitals are symmetrical

A

s

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33
Q

as l increases, the number of orbitals in given subshell

A

increases and shapes become more complex

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34
Q

d orbitals

A

subshells with l=2 have 5d orbitals, the first shell to have a d subshell is n=3

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35
Q

f orbitals

A

principle shells with n=4 can have subshells with l=3 ad ml values of -3,-2,-1,0,1,2,3; subshells consist of 7 f orbitals

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36
Q

orbital energies

A

depend only on principle quantum number(n)- energies of 2s, 2p, and 2d are all equal

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37
Q

spin quantum number

A

(ms) complete quantum phenomenon with no reaction to other quantum numbers and can’t be derived from solving Schrodinger’s equations, describes an intrinsic electron “rotation” or “spinning” [alpha state- spin up, beta state- spin down] ms value = +-1/2

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38
Q

magnet has lower energy if its magnetic momentum is aligned witht he external magnet field and higher is opposite to applied field

A

this is why ms +1/2 has slightly lower energy in an external field in positive z direction than ms+-1/2

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39
Q

Pauli Exclusion Principle

A

no 2 electrons in the same atom can have exactly the same set of all 4 quantum numbers (can share n,l,ml only if ms have different values and because ms can only be +-1/2 any atomic orbital can be populated by only 0, 1 or 2 electrons

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40
Q

black body radiation

A

radiation(light) given off by hot bodies, the intensity is a function of wavelength, distribution is a function of the temperature

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41
Q

quantized

A

positions that are fixed and can’t be in between 2 points

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42
Q

continuous

A

positions that can be anywhere on a spectrum

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43
Q

is energy absorbed or released when an electron goes from n=4 energy level to n=2 energy level

A

released, down arrow=energy releasing (up arrow is absorbing energy)

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44
Q

rydberg equation energy of a photon

A

2.179(or J given from atom being used)*10^-18((1/nf^2)-(1/ni^2))

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45
Q

what is the color of this photon equation

A

E=hc/wavelength

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45
Q

should electromagnetic radiation be described as a wave or a particle

A

evidence that its a wave: undergoes diffraction
evidence that its a particle: photoelectric effect, blackbody radiation

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46
Q

in a spectrum summary (chart with lines pointing up and down showing electrons going from one state to another)

A

the smallest energy change is the longest wavelength

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46
Q

wave-particle duality equation

A

wavelength= plancks constant/ mass * velocity

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46
Q

electrons are described by wave functions… Schrodinger’s equation allows for the calculation of
-the energy levels available for the electrons in an atom
-the probability of finding an electron at a particular place in an atom

A

results of the equation
-electrons are found in atomic orbitals
-the exact location of an electron can never be pinpointed, but the probability of an electron being in a particular location can be calculated

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47
Q

a group of atomic orbitals in a subshell constitutes a

A

subshell in a shell

48
Q

how many atomic orbitals constitute the n=3 shell

A

9, n^2

48
Q

a group of subshells constitutes a

A

shell or principle of energy level

49
Q

shell

A

principle quantum number n+=1, 2, 3; describes orbital size and energy

50
Q

subshell

A

Azimuthal Quantum Number l=0, 1, 2…(n-1); s p d ; orbital shape

51
Q

orbitals

A

magnetic quantum number ml= -1, 0, 1; orbital direction

52
Q

what are quantum numbers associated with the 1s subshell

A

n=1, l=0, ml=0

53
Q

Application of Paulis Expulsion Principle and the number of electrons allowed in specified orbitals; how many electrons can there be in the 1s orbitals and what are the corresponding 4 quantum numbers for both of these electrons?

A

2 electrons in 1s orbital
1,0,0,1/2
1,0,0,-1/2

54
Q

orbital energies

A

differing from orbital diagram in previous sections cause now we have more than one electron

55
Q

repulsion between electrons make the energies of subshells with different values of l differ

A

the energies of the orbitals increase within a shell in the order s<p<d<f

56
Q

electrons in successive atoms on the periodic table

A

tend to fill low energy orbitals first (this is why 4s, 3d, 4p)

57
Q

as n increases the size of the orbital increase sand electrons spend more time farther from the nucleus therefore

A

attention to nucleus is weaker and energy is associated with orbital is higher (less stabilized)

58
Q

electron configuration

A

arrangement of electrons in the orbitals of an atom describe with symbol containing 3 pieces of info
-# of principle quantum numbers
-letter that designates orbital type
-superscript number that designates the number of electrons in particular subshell

59
Q

aufbau principle

A

-to determine the electron configuration for any particular atom we can build the structures in the order of atomic numbers
-beginning with hydrogen and continuing across the periods er add one proton at a time to the nucleus and one electron to the proper subshell until we have described the electron configurations of all the elements

60
Q

writing orbital diagrams

A

pictorial representations of the electron configuration, showing individual orbitals and pairing arrangement of electrons

61
Q

noble gas configuration

A

abbreviation that consists of the elemental symbol of the last noble gas prior to that atom followed by configuration of remaining electrons

62
Q

exceptions for electron configuration

A

-subshells with similar energy and small effects can lead to changes in order of filling
-in cases of Cr and Cu we find half-filled and completely filled subshells represent conditions of preferer stability

63
Q

ionic compounds

A

complete transfer of electrons

64
Q

covalent compounds

A

sharing of electrons

65
Q

valence electrons

A

electrons don’t participate in chemical behavior

66
Q

core electrons

A

electrons don’t participate in chemical behavior

67
Q

for main group elements

A

number of valence electrons is given by group number

68
Q

coulombs law

A

says the force between 2 charged particles is dependent on the distance between the charges; the further the electron from the nucleus the less pull itll feel from the positively charged protons

69
Q

potential U

A

constant * (Q1Q2)/d Q1charge on proton Q2 charge on electron

70
Q

Z

A

number of protons in the nucleus

71
Q

Z effective

A

estimate of the effective nuclear charge felt by an electron in an atom

72
Q

EX hydrogen atom

A

the outer most electron is in the 1s shell, experiments confirm that both Z and Zeff are H

73
Q

due to shielding the electrons closest to the nucleus

A

decreases the amount of nuclear charge affecting the other electrons caused by the partial screening of nuclear charge by core electrons

74
Q

equation to estimate the effective nuclear charge for any given charge for any given atom or ion

A

Zeff= Z-S (protons(atomic number) -core electrons

75
Q

the total energy of the atom or ion, when more than one electron is present, depends on the

A

not only on the attractive electron nucleus interactions but also on repulsive electron-electron interactions

76
Q

the Zeff experienced by an electron in a given orbital

A

depends on the spatial distribution of the electron in that orbital and on the distribution of all other electrons present

77
Q

shielding is determined by

A

the probability of another electron being between the electron of interest and the nucleus

78
Q

Zeff for valence electrons increases

A

as we move from left to right across a period

79
Q

atomic radius

A

the radius of a sphere that represents an atom (1/2 the distance between the nuclei of 2 identical atoms when joined by covalent)

80
Q

atomic radii is determined by

A

measuring bond lengths between 2 bonded atoms

81
Q

Cl-Cl bond length is 1.99 so the atomic radius is

A

0.99

82
Q

ionization energy

A

the energy needed to remove an electron from an atom or cation in the gas phase; process can be written as a thermochemical equation(Na(g)->Na2+(g)+e-

83
Q

first ionization energy equation

A

represents the first electron removed form a atom

84
Q

second ionization energy

A

removing a second electron from atom

85
Q

electron affinity

A

the energy change when an electron is added to a gaseous atom to form an ion

86
Q

another definition of ionization energy

A

the energy needed to move a ground-state electron to the n=infinity energy level

87
Q

valence electrons play biggest role in

A

chemical equations cause they’re in outer most shell, have the highest energy

88
Q

elements in the same group(column)

A

have same number of valence electrons

89
Q

similarity in chemical properties among elements of the same group occurs because

A

same number of valence electrons, its the loss, gain or sharing that defines how they react

90
Q

main group elements

A

last electron added enters s or p orbital in outermost shell

91
Q

transition elements or metals

A

metallic elements in which the last electron added occupies a d orbital; valence electrons in these elements include the ns and (n-1) d electrons

92
Q

inner transition elements

A

metallic elements in which the last electron added occupies an f orbital; valence shells consist of the (n-2) f and (n-1)d and ns subshell; two inner transition series: 1. lanthanide series: lanthanum (La) through lutetium(Lu) 2. actihide series: actinium (Ac) through lawrencium (Lr)

93
Q

variation in atomic radius

A

as we scan down a group n increases by 1 for each element; this shows electrons being added to a region of space that is increasingly distant from the nucleus, the size of atoms increase as you increase the distance of the outermost electrons from the nucleus to the

94
Q

variation in ionization energies

A

energy is always required to remove electrons from atoms or ions

95
Q

as Zeff for the valence electrons increase from left to right the first ionization energy increases too

A

because more energy will be required to remove electrons

96
Q

as n level for the valence electrons increases down a group the atoms get

A

bigger and the coulombic attraction between nucleus and valence electrons decreases; valence electrons become easier to remove and first ionization energy decreases

97
Q

ion

A

an atom or molecule that has gained or lost one of its valence electrons resulting in a positive or negative net charge

98
Q

cation

A

a positively charged ion that has more protons than electrons (when electrons are removed from parent function)

99
Q

anion

A

a negatively charged ion that has more electrons than protons

100
Q

(hw11) the magnitude of the enthalpy of vaporization is a direct indication

A

of the intermolecular forces of the a liquid

101
Q

electron affinity

A

the amount of energy released when an electron is added to a neutral form of an atom to form an anion

102
Q

probability density distributions contain

A

90% probability of the electrons being in that region

103
Q

4(wavefunciton)r^2

A

the probability of finding the electron at all points in space at distance r

104
Q

in a radial distribution graph function most electrons

A

are found close to the nucleus and the graph is highest right away, farthest left

105
Q

the highest point of the graph is

A

where it is most probable to find an electron from the nucleus

106
Q

how to determine the number of spherical nodes for a given orbital

A

n-L-l

107
Q

number of nodal planes

A

L

108
Q

electron spin is quantized

A

ms= 1/2 or -1/2

109
Q

Pauli Exclusion Principle

A

no two electrons in an atom can have the same set of four quantum numbers

110
Q

paramagnetic

A

contains 1 or more unpaired electron when looking at the electron configuration boxes

111
Q

diamagnetic

A

all electrons are paired in orbitals

112
Q

determining Zeff

A

Zeff=Z(atomic number)-S(core electrons)

113
Q

transition metal electron configuration

A

electrons in s orbital are easier to remove than from d or f electrons, highest ns electrons are lost first then (n-1)d electrons are removed

114
Q

main group metals

A

the electrons that were added last are first electrons removed; cation is formed when electrons are removed from parent function

115
Q

main group nonmetals

A

added electrons fill in order predicted by Aufbau principle; anions form when one or more electrons are added to parent atom

116
Q

ferro magnetism

A

occurs when certain metals act as permanent magnets, due to presence of unpaired electrons

117
Q

paramagnetism

A

occurs when an atom or ion is attracted to a magnetic field, due to unpaired electrons

118
Q

diamagnetism

A

occurs when an atom or ion isn’t attracted to a magnetic field; due to all electrons being paired

119
Q

atomic radii of cations

A

cations have fewer electrons and same number of protons than parent atom so it has a smaller atomic radii than the parent atom

120
Q
A