CHEM 103: Test 2
Which of the following is an acceptable value of the spin quantum number? Select all that apply. +1/2 -1/2 0 1
+1/2 -1/2 For any electron in any atom, the only two possible values of the spin quantum number are +12 and -12, denoting each of the two opposite "spins" of the electron.
If l=0,ml must be: 0 1 −1 2
0 Zero would be the only allowed value in this instance since if l=0, then the electron has an s orbital (spherical shape) and does not have any angular momentum (i.e. vector does not point in any direction). Therefore, if l= 0 then ml must also = 0.
What is the electron configuration for V2+
1s2 2s2 2p6 3s2 3p6 3d3
What is the electron configuration of Ge?
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2.
What is the electron configuration of strontium?
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2
How many electrons can fit inside an atomic orbital? 0 1 2 3
2 A maximum of two electrons can fit within an atomic orbital, which is why they must have opposite spin values.
Which of the following formulas gives us the total number of possible orbitals with the same value of l? 2l−1 2l+1 2l3 2l
2l+1 2l+1 gives us the total number of possible orbitals with the same value as l. For example, the p orbital has a value of l=1. This means there can be three p orbitals, (2⋅1)+1.
What is the change in energy for an electron of a hydrogen atom that is excited from a n=2 orbit to a n=5 orbit, in joules?
4.58×10^−19J.
Which element, when it loses 3 electrons, will have the electron configuration 1s22s22p6?
Al Aluminum is the third element in period 3 so when it loses three electrons it will have neon electron configuration.
Which of the following statements about the photoelectric effect is true? Beyond the threshold energy, increasing the energy of the photons increases the kinetic energy of the ejected electrons. Beyond the threshold intensity, increasing the intensity of the incoming light increases the kinetic energy of the ejected electrons. Beyond the threshold amount, increasing the amount of incoming light increases the kinetic energy of the ejected electrons. all of the above
Beyond the threshold energy, increasing the energy of the photons increases the kinetic energy of the ejected electrons. Increasing the energy of the photons increases the kinetic energy of the ejected electrons.
The wavelength of radiation is 7.0×10−7 m. What is the energy (in Joules) of the photon emitted? Use 3.00×10^8m/s for the speed of light. Report your answer in scientific notation. Use the multiplication symbol (×) on the toolbar in your answer. Remember to use correct significant figures in your answer (round your answer to the nearest tenth).
E = hc / wavelength = 2.8*10^-19 J
Which of the following phenomena can only be explained by considering the wave nature of light? Reflection Refraction Interference None of the above
Interference Early in the nineteenth century, Thomas Young demonstrated that light passing through narrow, closely spaced slits produced an interference pattern that could not be explained in terms of Newtonian particles, but could be easily explained in terms of waves. Phenomena such as reflection and refraction can be equally well explained in terms of light travelling as high-speed waves or as high-speed particles.
Schrodinger was able to build off of the work of ________ to determine that electrons should be thought of in terms of wave functions. Erwin Schrodinger Max Born Louis de Broglie Werner Heisenberg
Louis de Broglie Schrodinger was able to build off of the work of Louis de Broglie to determine that electrons should be thought of in terms of wave functions.
What is the symbol for the following ion electronic structure: [Ne]3s23p6 with an atomic number of 16?
S2- Atomic number 16 corresponds to S but there are 2 more electrons than S usually has so we know that S had to gain (−2).
Which element, when it gains two electrons, will have the electron configuration 1s22s22p63s23p64s23d104p6?
Se
The Heisenberg uncertainty principle does not apply when measuring which pair of observable quantities? The position or momentum of an electron. The energy and momentum of an electron. The vector components of angular momentum for an electron. The time required for an electron to undergo an energy transition and the change in the energy of the electron.
The energy and momentum of an electron. The Heisenberg Uncertainty Principle states that It is fundamentally impossible to determine simultaneously and exactly both the momentum and the position of a particle. Heisenberg's uncertainty principle is not just limited to uncertainties in position and momentum, but links other physical variables as well. For example, the uncertainty in the energy and the uncertainty in the time required for the transition are related to the Heisenberg Uncertainty Principle. For certain quantities, such as the energy and the momentum of an electron, the Heisenberg uncertainty principal does not not apply
According to the Heisenberg uncertainty principle, quantum mechanics differs from classical mechanics in that: Quantum mechanics involves particles that do not move. It is impossible to calculate with accuracy both the position and momentum of particles in classical mechanics. The measurement of an observable quantity in the quantum domain inherently changes the value of that quantity. All of the above
The measurement of an observable quantity in the quantum domain inherently changes the value of that quantity. Quantum mechanics differs from classical mechanics in that measurements of certain observables in the quantum domain introduce changes to the system, a fact that is governed mathematically by Heisenberg's uncertainty principle.
Which of the following is true according to Heisenberg's uncertainty principle? There is always uncertainty when working with macroscopic objects. There is no feasible way to know how many electrons are in an atom. The product of the uncertainties in momentum and position of an electron is bounded by a constant. It is impossible to determine the mass of an electron.
The product of the uncertainties in momentum and position of an electron is bounded by a constant. Mathematically, the Heisenberg Uncertainty Principle states that: ΔxΔpx≥ℏ2 This fundamentally limits the product of the uncertainties associated with a particle's position and momentum, thus limiting the precision with which we know each at a given instant.
What is the electron configuration for Zr?
[Kr]5s2 4d2
What is the electron configuration of phosphorus (P)?
[Ne]3s2 3p3
At the end of the 19th century, light was viewed as being: a particle a wave both a particle and a wave none of the above
a wave Due to work by various physicists, the common view was that light could be adequately described as being merely a wave.
For the purposes of determining electron configuration of ions, when electrons are added to a neutral atom, they will inhabit orbitals according to: the Pauli exclusion principle the Aufbau principle Hund's rule all of the above
all of the above Adding additional electrons to neutral atom to form a negative ion follows the same principles that affect the electron configuration of a neutral atom.
By calculating the change in energy of the electron as it changes orbits, we can also calculate: the energy of the photon absorbed or emitted the wavelength of the photon absorbed or emitted the frequency of the photon absorbed or emitted all of the above
all of the above All of these above quantities are related, and thus can all be calculated from the corresponding energy change of the electron.
The work of which of the following people lent itself to the establishment of quantum mechanics? Werner Heisenberg Erwin Schrodinger Louis de Broglie all of the above
all of the above The work of Heisenberg, Schrodinger, de Broglie, and other scientists led to the work of quantum mechanics. They discovered that classical mechanics did not fully explain the wave-particle duality of quantum particles. Hence, the field of quantum mechanics was established.
Which of the following distinguishes the different shapes of orbitals? magnetic quantum number, ml spin quantum number, ms principal quantum number, n angular momentum quantum number, l
angular momentum quantum number, l The angular momentum quantum number, l, distinguishes the different shapes of orbitals.
Increasing the _______ of incoming light can cause an increase in the number of ejected electrons. wavelength brightness energy cycle
brightness The brightness of incoming light, or the number of photons striking the surface within a given time period, can cause an increase in the number of ejected electrons.
The current view proposes that light is: composed of waves composed of particles (corpuscular) composed of both waves and particles (wave-particle duality) interference
composed of both waves and particles (wave-particle duality) Newton believed light was composed of particles and Maxwell believed light was composed of waves, but we now believe light is both wavelike and particle-like.
The view of light that describes light as consisting of particles is called: particulate spherical discrete corpuscular
corpuscular A corpuscle refers to a tiny particle, hence the view that light consists of particles is the corpuscular view of light.
As n increases, the distance between the energy levels: increases decreases stays the same there is no distance between the energy levels
decreases With each successive orbit, the distance to the next orbit becomes smaller.
The electron removed when a neutral atom loses an electron will always be an electron from the: 1s orbital lowest energy orbital highest energy orbital 3d orbital
highest energy orbital The highest energy electron is removed, which will be in the highest energy orbital which would be the valence electrons.
What did Schrodinger study in order to build his theory? electron wavelengths nuclear patterns hydrogen-like atoms carbon-like atoms
hydrogen-like atoms Schrodinger studied hydrogen-like atoms to establish his theory. He then developed the equation (H^ψ=Eψ).
Every ________ will have its own unique set of quantum numbers. atom shell of electrons proton individual electron
individual electron Every single electron in an atom will have a unique set of quantum numbers describing its energy and orientation within the atom.
If an electron reaches n=∞, the electron: achieves infinite energy achieves negative energy emits a photon is ejected from the atom
is ejected from the atom The energy level represented by n=∞ is actually a finite distance away from the nucleus, so to surpass this energy level is to be ejected from the electron.
Which of the following labels are used for quantum numbers to describe the state of an electron inside an atom? Select all that apply. l m mo ms
l ms The magnetic quantum number (ml), the spin quantum number (ms), the principal quantum number (n), and the angular momentum quantum number (l) all describe electrons within atoms. (m) and (mo) are not labels used to describe the state of an electron in an atom.
Which of the following quantum numbers describes an electron in an atom? Select all that apply. l n ml ms
l n ml ms The magnetic quantum number (ml), the spin quantum number (ms), the principle quantum number (n), and the angular momentum quantum number(l) all describe an electron.
An atom has an n value of 1. What is its l value and orbital type? l=0 orbital type=s l=1 orbital type=p l=2 orbital type=p l=3 orbital type=f
l=0 orbital type=s l is the angular momentum quantum number. Its value is between 0 and n−1. If an atom has an n value of 1 then its l value must be 0 because 1−1=0. The l value describes the shape of the orbital, and when l=0 we are describing s orbitals which are spherical.
The Heisenberg uncertainty principle imposes: definitive knowledge about certain systems constraints on scientific constants limits on what can be known in science none of the above
limits on what can be known in science The Heisenberg uncertainty principle tells us that there are things we cannot know in science, such as the location and momentum of an electron simultaneously.
Which of the following signifies the spatial orientation, i.e. direction, of an atomic orbital? magnetic quantum number, ml spin quantum number, ms principal quantum number, n angular momentum quantum number, l
magnetic quantum number, ml The magnetic quantum number, ml, signifies the spatial orientation of an atomic orbital.
Which of the following formulas gives us ml, the total number of possible orbitals within a subshell? ml=2l−1 ml=2l+1 ml=2l3 ml=2l
ml=2l+1 ml=2l+1, the magnetic quantum number, gives us the total number of possible orbitals within a particular subshell.
Which electron spin state has the lower energy in the absence of an external magnetic field? ms=+12 ms=−12 ms=+12 and ms=−12 have the same energy. There is not enough information to answer this question.
ms=+12 and ms=−12 have the same energy. The magnetic spin states have the same energy in the absence of a magnetic field.
The visible lines on hydrogen's emission spectrum all result from electron transitions ending in what n value?
n = 2
An electron in an unknown energy level of a hydrogen atom transitions to the n=2 level and emits a photon with wavelength 410 nm in the process. What was the initial energy level?
n1 = 6.008 = 6
Which set of quantum numbers is invalid? n=1,l=1,ml=0,ms=12 n=2,l=0,ml=0,ms=−12 n=3,l=1,ml=0,ms=12 n=2,l=1,ml=−1,ms=−12
n=1,l=1,ml=0,ms=12 The principle quantum number is n. The angular momentum quantum number, l, must be an integer from 0 to n−1, inclusive. The magnetic quantum number, ml, must be an integer between −l and l, inclusive. Therefore, l must be less than n, so the set of quantum numbers, n=1,l=1,ml=0,ms=12, is invalid.
Which set of quantum numbers is invalid? n=3,l=1,ml=0,ms=−12 n=1,l=0,ml=0,ms=12 n=5,l=3,ml=−3,ms=−12 n=2,l=0,ml=−1,ms=12
n=2,l=0,ml=−1,ms=12 Since l =0 indicates a s-orbital (sphere-shaped), there are no additional vector directions and the magnetic quantum number ml must also be zero. Therefore, the option n=2,l=0,ml=−1,ms=12 does not represent a valid set of quantum numbers.
Electrons that inhabit different orbitals must have a different value for the: principal quantum number angular momentum quantum number spin quantum number none of the above
none of the above They could have the same principal quantum number if they are in different orbitals with the same shell, they could have the same angular momentum quantum number if they are in different orbitals of the same type of subshell, and they could have the same spin value, as every full orbital will have one electron spin up and one spin down.
Given the following quantum numbers n=4,l=1,ml=−1,0,1, what is the subshell of the orbital? s p d f
p An l value of 1 indicates a p subshell.
The _____________________ defines the general value of the electronic energy, while the _____________________________ determines the shape of the orbital.
principal quantum number; angular momentum quantum number The principal quantum number corresponds to the energy of an orbital (as in the Bohr model), while the angular momentum quantum number corresponds to the unique shape of the orbital (labeled s,p,d, or f).
Which of the following orbitals (or subshells) has a spherical shape? f d s p
s The s subshell has a spherical shape.
In Schrodinger's equation (H^ψ=Eψ), H^ is called the Hamiltonian operator. What does the hamiltionian operator represent? the actual total energy of the particle the wavefunction of the particle set of mathematical operations representing the total energy of the particle none of the above
set of mathematical operations representing the total energy of the particle H^ in Schrödinger's equation is the Hamiltonian operator: the specific set of mathematical operations representing the total energy of the particle.
Electrons that reside in the same orbital must have different values for their: angular momentum quantum number principal quantum number magnetic quantum number spin quantum number
spin quantum number If two electrons reside in the same orbital, they have the same values for all the quantum numbers except spin, which must then be opposite in value to represent spin up and spin down.
Which of the following quantum numbers can only take on values of +12 or −12? magnetic quantum number, ml spin quantum number, ms principal quantum number, n angular momentum quantum number, l
spin quantum number, ms The spin quantum number, ms, indicates the direction of the electron spin. The spin quantum number can only take on values of +12 or −12.
Calculate the change of energy for an electron within a hydrogen atom that undergoes a transition from n=3 to n=4.
the change in energy is approximately 1.06×10^−19J
The quantum-mechanical model of the atom changed our view of which subatomic particle? the electron the proton the neutron the positron
the electron In the quantum-mechanical model of the atom, electrons are viewed as clouds of probability density. This revolutionized our view of the atom because it allowed us to better understand the shapes of individual atoms and the attraction between them.
The principal quantum number, n, corresponds to: the electron's spin the type of orbital the electron resides in the energy level of the electron an individual orbital within a subshell
the energy level of the electron The principal quantum number refers to the energy level, just as in the Bohr model.
The greater the frequency of the photon that strikes a metal: the fewer electrons that will be ejected the more electrons that will be ejected the greater the potential energy of an ejected electron the greater the kinetic energy of an ejected electron
the greater the kinetic energy of an ejected electron Only one electron will be ejected by a particular photon. Above the threshold frequency, higher frequency means more kinetic energy imparted onto the ejected electron.
Light intensity depends on: the wavelength of the incoming wave the frequency of the incoming wave the number of photons striking the surface during a given time period all of the above
the number of photons striking the surface during a given time period Einstein argued that light intensity depends on the number of photons striking the surface during a given time period. This explains why the number of ejected electrons increases with increasing brightness, since increasing the number of incoming photons increases the likelihood that they will collide with electrons.
The energy difference of a photon is 8.3×10^−20 J. From this number we know that: the photon is being absorbed the photon is being reflected the photon is being repelled none of the above
the photon is being absorbed If the energy difference of a photon is 8.3×10^−20 J, we know that the photon is entering the system and is being absorbed to excite the electron.
Wavefunctions can be used to determine: the momenta of electrons orbital radii the probable distribution of electron density in an atom none of the above
the probable distribution of electron density in an atom Wavefunctions are complex probability amplitudes which tell us about the distribution of electron density in an atom in a probabilistic way.
In order to solve the photoelectric effect, Einstein applied quantization to which parameter? the orbital energy of an electron the vibrational energy of atoms the velocity of an electron the structure of light
the structure of light Einstein's solution required that light be viewed as particles, or quanta, rather than continuous waves.
The angular momentum quantum number, l, corresponds to: the electron's spin the type (or shape) of orbital the electron resides in the energy level of the electron an individual orbital within a subshell
the type (or shape) of orbital the electron resides in Each value for the angular momentum quantum number will correspond specifically with s,p,d, or f orbitals, which each have their own distinct shapes.
The Heisenberg uncertainty principle states that there is a fundamental limit to how precisely both the position and momentum of electrons and other quantum particles can be known. This limit is due to _________. the inability to see electrons limitations in mathematical models for momentum the wave-like nature of an electron the particle-like nature of an electron.
the wave-like nature of an electron Because the electron is so small, its behavior is heavily influenced by its wave-like properties. Particles have well defined positions and momenta, while waves do not. This uncertainty exists for all objects (even macroscopic) but only for extremely low mass particles like electrons does the uncertainty become large enough to affect measurements and predictions of particle behavior in any meaningful way.
Which of the following statements are true according to the Pauli exclusion principle? not all electrons have a spin quantum number (ms) there are a maximum of two electrons in each orbital no two electrons can have the same four electronic quantum numbers the two electrons in each orbital must have opposite spins
there are a maximum of two electrons in each orbital no two electrons can have the same four electronic quantum numbers the two electrons in each orbital must have opposite spins The Pauli Exclusion Principle states that, in an atom, no two electrons can have the same four electronic quantum numbers. This means that at least one of their n,l,ms,ml values must be different. The Pauli Exclusion Principle also implies that a maximum of two electrons can be found in one orbital, and the two electrons must have opposite spins.
The complementary values most widely associated with the Heisenberg Uncertainty Principle are momentum (p) and location (x). Another set of complementary variables for which this principle applies is which of the following? velocity and time mass and time energy and velocity time and energy
time and energy Momentum and location are inextricably related to the time and energy of an electronic transition (which constitute another set of complementary values). This means that the Heisenberg Uncertainty Principle applies to these variables as well: reduced uncertainty in one means greater uncertainty in another.
Einstein's solution to the photoelectric effect was the first introduction to the true nature of light as obeying: solely particle-like behavior solely wave-like behavior amplitude stability wave-particle duality
wave-particle duality Wave-like properties of light had already been well-documented, so the confirmation of particle-like behavior offered the first insight into wave-particle duality for light.
If an electron transitions from n=4 to n=1, what will be the wavelength of the resulting photon emitted? Use RH=2.179×10^−18J for the hydrogen atom Rydberg constant. Use h=6.626×10^−34 Js for Planck's constant. Use c=2.998×10^8ms for the speed of light.
ΔE = -RH (1/nf^2 - 1/ni^2) ΔE = hc/wavelength wavelength = 9.724x10^-8 m
What is the energy change of a hydrogen atom when it moves from the n = 4 energy level to the n = 1 energy level? −2.043×10^−18 J 2.043×10^−18 J 1.634×10^−18 J −1.634×10^−18 J
−2.043×10^−18 J
