chapter 6 Bohr's atomic theory
Schrodinger was able to build off of the work of ________ to determine that electrons should be thought of in terms of wave functions.
Louis de Broglie
Who is credited with thinking of the electron "waves" as complex probability amplitudes?
Max Born
Given the following quantum numbers n=4,l=1,ml=−1,0,1, what is the subshell of the orbital?
p An l value of 1 indicates a p subshell.
Each row on the periodic table corresponds to which quantum number for s and p orbitals?
principal quantum number
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
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.
What are the properties of ferromagnets?
They have permanent magnetic dipole moments. Unpaired electrons in these substances have aligned spins. They can lose their permanent magnetic dipole when heated. A ferromagnetic material has all of the unpaired electrons aligned in the same direction. This causes ferromagnetic materials to possess a permanent magnetic dipole moment, but this alignment can be removed by heating above the Curie temperature.
The Aufbau principle states that:
Orbitals will be filled in order of increasing energy, which is generally in order of increasing principal quantum number. It is the Aufbau principle that outlines the precise order in which orbitals will be filled when an atom houses its electrons. The Pauli Exclusion Principal states that no two sets of quantum numbers can be the same. Hund's Rule states that you must place one electron in each orbital in a subshell before doubling up.
Which of the following states that electrons orbiting one or more atoms must fill the lowest available energy level first, and then "build up" to higher levels?
The Aufbau principle states that electrons orbiting one or more atoms must fill the lowest available energy level first, and then "build up" to higher levels. Each orbital can hold a maximum of 2 electrons because of the Pauli Exclusion principle, which states that no two electrons in the same atom can have exactly the same set of all four quantum numbers. Finally, Hund's rule states that for incompletely filled subshells, electrons fill different orbitals before doubling up within the same orbital. The Heisenberg Uncertainty Principle does not apply to assigning electron configuration.
According to the Aufbau rule, what is the electron configuration of iron?
The Aufbau principle states that electrons will fill atomic orbitals with the lowest energy before occupying orbitals with higher energy. The order by which electrons fill atomic orbitals is shown in the diagram below.
Which of the following quantum numbers describes an electron in an atom? Select all that apply.
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.
According to the Heisenberg uncertainty principle, quantum mechanics differs from classical mechanics in that:
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.
True or false: According to the Heisenberg principle, the exact position and momentum of a particle cannot be determined simultaneously.
True The Heisenberg uncertainty principle imposes a fundamental limit on what is knowable in science. In particular, Werner Heisenberg determined that there is a fundamental limit to how accurately both a particle's position and its momentum can be simultaneously measured. In fact, the more accurately the momentum of a particle is measured, the less accurately its position can be determined at that time, and vise versa.
What did Schrodinger study in order to build his theory?
hydrogen-like atoms Schrodinger studied hydrogen-like atoms to establish his theory. He then developed the equation (H^ψ=Eψ).
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, 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 signifies the spatial orientation, i.e. direction, of an atomic orbital?
magnetic quantum number, ml
Which set of quantum numbers is invalid?
n=1,l=1,ml=0,ms=12, is invalid 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=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.
The 5p orbitals fill immediately after the 4d orbitals and immediately before the 6s based on: (select all that apply)
observed experimental results theoretical calculations The 5p orbitals fill immediately after the 4d orbitals and immediately before the 6s based on observed experimental results, and has been supported by theoretical calculations.
The angular momentum of an electron will be:
perpendicular to its orbit The angular momentum of an object in circular motion, whether an electron or a macroscopic object, will be perpendicular to the plane of circular motion.
The model for the atom that was understood when Bohr made his contributions was called the:
planetary model It was called the planetary model because it was thought that the electrons orbiting the nucleus must resemble planets orbiting a star.
In the equation that predicts the change in energy of an electron, the n values must be:
positive integers
When wave-particle duality was applied to the electron, it explained why the energy of the electron is quantized because:
the electron is a standing wave that can only have an integer number of wavelengths If the electron is viewed as a circular standing wave, it must be uninterrupted and therefore it must have an integer number of wavelengths and an integer number of nodes. This means it will have quantized energy.
Wavefunctions can be used to determine:
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.
A He atom with a mass of 6.65×10−27 kg has a de Broglie wavelength of 4.3×10−12 m. What is the velocity of the He atom, in meters per second? Use 6.626×10−34kg m2s for Planck's constant.
2.3×10 ^4ms
Which would be an invalid listing within an electron configuration?
2d5 There are no 2d orbitals, so even though 5 is an acceptable number for d occupancy, this listing can not exist in an electron configuration. The following image shows the orbitals and the correct order that they will be filled.
The orbitals that are next highest in energy after the 4s orbital are the:
3d Somewhat against intuition, the 3d orbitals are next in terms of energy following the 4s orbital. The image below shows the order for filling orbitals from lowest to highest energy.
The orbitals that are usually the next highest in energy after the 6s orbitals are the:
4f
For an atom, electrostatic potential is also called:
Coulomb potential These terms are synonymous, as Coulombs deal with electric charge.
Which of the following is a rule indicated by the Aufbau principle?
Electrons are placed in the lowest energy subshell that is not fully occupied. The Aufbau principle indicates that electrons are placed in the lowest energy subshell that is not already fully occupied. This order is illustrated by the image below. Different subshells have different capacities and each subshell will be filled before moving on to the next subshell. The s subshells hold 2 electrons. The p subshells hold 6 electrons. The d subshells hold 10 electrons. The f subshells hold 14 electrons.
Which of the following types of material contain atoms with at least one unpaired electron?
Ferrimagnetic, ferromagnetic, and paramagnetic materials all have unpaired electrons. In ferrimagnetic materials, the spins of the unpaired electrons are aligned in opposite directions but are not all equal in magnitude, so the material has a slight net magnetism. In ferromagnetic materials, the electron spins align with one another to produce a permanent dipole moment. In paramagnetic materials, the electron spins are randomized. Diamagnetic substances do not have unpaired electrons.
Which type of material will have a permanent magnetic dipole moment in the absence of an external magnetic field?
Ferromagnetic and ferrimagnetic materials both have permanent magnetic dipole moments in the absence of an external magnetic field. The electrons in a ferromagnet are all aligned, whereas electrons in a ferrimagnet are aligned in opposite directions but with unequal magnitudes, so there is a permanent magnetic dipole moment.
Which of the following is true according to Heisenberg's uncertainty principle?
The product of the uncertainties in momentum and position of an electron is bounded by a constant. Mathematically, the Heisenberg Uncertainty Principle states that: Δx Δp x ≥ ℏ/2 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.
How do compounds with no unpaired electrons interact with external magnetic fields?
They are weakly repelled by magnetic fields. Diamagnetic compounds contain only pairs of electrons. They are very weakly repelled by external magnetic fields.
Which will have the shortest wavelength for a given energy? an electron a hydrogen atom a bacterium a baseball
a baseball The greater the mass of an object, the shorter its wavelength, as they are inversely proportional. So macroscopic objects have incredibly tiny wavelengths that are negligible, unlike subatomic particles.
Which of the following distinguishes the different shapes of orbitals?
angular momentum quantum number, l
Electrons in orbitals that experience shielding:
are less stabilized have higher energy
The success of Bohr's model that demanded the scientific community's attention was its ability to:
calculate the Rydberg constant The Rydberg constant was one of the most precisely measured constants of the time, so when Bohr's model calculated this constant to be in excellent agreement with the experimentally determined value, it was impossible to deny the validity of his model for the hydrogen atom.
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 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.