Lesson 3: Quantum Numbers Flashcards
Why doesn’t Hydrogen produce a continuous spectrum of light?
Because its orbitals have specific energy differences between them, resulting in light waves with specific energy levels and thus specific wavelengths. It cannot produce every different wavelength level.
What is the Rydberg equation for hydrogen, which relates wavelength of light emitted to the orbital level change of an electron?
(1/λ) = R((1/nf^2) - (1/ni^2)) λ = Wavelength R = Rydberg’s Constant (1.097 ⋅ 10^7) nf = Final Orbital Level ni = Initial Orbital Level
An electron within Hydrogen jumps from the second orbital to the first orbital. What wavelength of light is emitted considering that Rydberg’s constant is 1.097 ⋅ 10^7? (A) 6.78 ⋅ 10^-4 (B) 1.22 ⋅ 10^-7 (C) 1.81 ⋅ 10^-9 (D) 8.43 ⋅ 10^-15
(B) 1.22 ⋅ 10^-7 (1/λ) = R((1/nf^2) - (1/ni^2)) (1/λ) = (1.097 ⋅ 10^7)((1/1^2) - (1/2^2)) (1/λ) = approx. (.75 ⋅ 10^7) 1/(.75 ⋅ 10^7) = λ 1.34 ⋅ 10^-7 = λ, which is closest to (B) 1.22 ⋅ 10^-7
According to the Heisenberg uncertainty principle, it is impossible to know what two things about a moving particle at the same time? (A) Position and momentum (B) Direction and position (C) Momentum and acceleration (D) Acceleration and direction
(A) Position and momentum According to the Heisenberg uncertainty principle, it is impossible to know the position and momentum of a moving particle at the same time.
True or false? The ability to know the position, and the ability to know the momentum of a moving particle are inversely related.
True. The ability to know the position, and the ability to know the momentum of a moving particle are inversely related. As the knowledge of one increases, knowledge of the other decreases.
How does the Heisenberg uncertainty principle apply to the Bohr model of the electron?
It is impossible to know the location and momentum of an electron at the same time, which proves the Bohr model to be an inaccurate representation of the atom.
Which is the symbol for the principal quantum number? (A) l (B) n (C) m(l) (D) m(s)
(B) n n is the symbol for the principal quantum number.
Which is the symbol for the angular momentum quantum number? (A) l (B) n (C) m(l) (D) m(s)
(A) l l is the symbol for the angular momentum quantum number.
According to spectroscopic notation, which of the following angular momentum quantum numbers is improperly matched with its corresponding letter? (A) l = 0 , s (B) l = 3 , f (C) l = 2 , d (D) l = 4, h
(D) l = 4, h According to spectroscopic notation, the angular momentum quantum numbers’ corresponding letters are: l = 0 (s), 1 (p), 2 (d), 3 (f), 4 (g), 5 (h), etc. (alphabetical order).
Which is the symbol for the magnetic quantum number? (A) l (B) n (C) m(l) (D) m(s)
(C) m(l) m(l) is the symbol for the magnetic quantum number.
Which is the symbol for the spin number? (A) l (B) n (C) m(l) (D) m(s)
(D) m(s) m(s) is the symbol for the spin number.
Which quantum number is also called the azimuthal quantum number, and includes integer values up to n-1? (A) l (B) n (C) m(l) (D) m(s)
(A) l The angular momentum quantum number, or azimuthal quantum number, may have integer values as large as n-1.
Which of the following terms refers to an atom that has all of its electrons spin-paired, and will be slightly repulsed by an external magnetic field? (A) Magnetic (B) Paramagnetic (C) Ferromagnetic (D) Diamagnetic
(D) Diamagnetic A diamagnetic atom has all of its electrons spin-paired, and will be slightly repulsed by a magnetic field. Noble gases are diamagnetic.
Which of the following terms refers to an atom that does not have all of its electrons spin-paired, and will be slightly attracted by an external magnetic field? (A) Magnetic (B) Paramagnetic (C) Ferromagnetic (D) Diamagnetic
(B) Paramagnetic A paramagnetic atom has some electrons that are not spin-paired, and will be slightly attracted by an external magnetic field.
What are the possible values of n, l, m(l), and m(s) for when n = 1? How many electrons are in this shell?
n = 1 l = 0 (s) m(l) = 0 m(s) = +1/2 (up) or -1/2 (down) # of electrons = 2
What are the possible values of n, l, m(l), and m(s) for when n = 2? How many electrons are in this shell?
n = 2 l = 0 or 1 (s or p) m(l) = -1, 0, or +1 m(s) = +1/2 (up) or -1/2 (down) # of electrons = 8
What are the possible values of n, l, m(l), and m(s) for when n= 3? How many electrons are in this shell?
n = 3 l = 0, 1, or 2 (s, p, or d) m(l) = -2, -1, 0, or +1, +2 m(s) = +1/2 (up) or -1/2 (down) # of electrons = 18
What are the possible values of n, l, m(l), and m(s) for when n= 4? How many electrons are in this shell?
n = 4 l = 0, 1, 2, 3 (s, p, d, or f) m(l) = -3, -2, -1, 0, or +1, +2, or +3 m(s) = +1/2 (up) or -1/2 (down) # of electrons = 32
Draw the shape of the s orbital(s).
1 orientation
Draw the shape of the p orbital(s).
3 orientations
Draw the shape of the d orbital(s) and f orbital(s).
d has 5 orientations f has 7 orientations
Match the following orbitals with how many electrons can coexist in each. I. f II. s III. p IV. d (A) 10 (B) 6 (C) 14 (D) 2
I. (C) an f orbital can house 14 electrons. II. (D) an s orbital can house 2 electrons. III. (B) a p orbital can house 6 electrons. IV. (A) a d orbital can house 10 electrons.
Compare the Aufbau principle, the Pauli exclusion principle, and Hund’s rule.
The Aufbau principle is the “building up” principle, which states that electrons will fill in lower energy orbitals first. The Pauli exclusion principle is the “unique address” principle, which states that no two electrons can have the same four quantum numbers. Hund’s rule is the “empty bus seat” rule, which states that electrons will fill in orbitals one at a time before pairing up.
Which of these principles requires that an electron in the same orbital as another electron must spin in the opposite orientation? (A) Aufbau principle (B) Pauli exclusion principle (C) Hund’s rule (D) Electron configuration principle
(B) Pauli exclusion principle
One anomaly to the above rules is that the lower energy state for d-block metals is to have a half-filled or filled d-subshell and have only one electron in its largest s-subshell. Which rule does this seem to violate? (A) Aufbau principle (B) Pauli exclusion principle (C) Hund’s rule (D) Electron configuration principle
(A) Aufbau principle
Regarding the Aufbau principle, which of the following sums of quantum numbers helps to rank orbitals in terms of energy? (A) n + m(s) (B) m(s) + m(l) (C) n + l (D) l + m(l)
(C) n + l The n + l rule helps to rank subshells by increasing energy.
What is the longhand electron configuration for Phosphorus (see periodic table here: https://www.ptable.com/Images/periodic%20table.png)? (A) 1s2 2s2 2p3 (B) 1s2 2s2 2p6 3s3 (C) 1s2 2s2 2p6 3s2 3p3 (D) 1s2 2s2 2p6 3s2 3p6 4d3
(C) 1s2 2s2 2p6 3s2 3p3
What is the shorthand electron configuration for Aluminum (see periodic table here: https://www.ptable.com/Images/periodic%20table.png)? (A) [He] 2s2 2p1 (B) [He] 3s1 (C) [Ne] 3s2 3p1 (D) [Ne] 4d1
(C) [Ne] 3s2 3p1
What is the shorthand electron configuration for Sc+ (see periodic table here: https://www.ptable.com/Images/periodic%20table.png)? (A) [Ar] 3d1 4s1 (B) [Ar] 3d2 (C) [Ar] 4d1 4s1 (D) [Ar] 4d2
(A) [Ar] 3d1 4s1 Note that the Scandium loses one of its 4s electrons and not its 3d electron when obtaining a +1 charge.
What is the shorthand electron configuration for Chromium (see periodic table here: https://www.ptable.com/Images/periodic%20table.png)? (A) [Ar] 3d5 4s1 (B) [Ar] 4s2 3d4 (C) [Ar] 4d5 4s1 (D) [Ar] 4s2 4d4
(A) [Ar] 3d5 4s1
Which of the following elements is diamagnetic (see periodic table here: https://www.ptable.com/Images/periodic%20table.png)? (A) Potassium (B) Calcium (C) Bromine (D) Sulfur
(B) Calcium To be diamagnetic, the atom must have an even number of electrons, eliminating (A) and (C). For (D), the 3p4 electrons will follow Hund’s rule, meaning 2 electrons are unpaired.
Atoms are isoelectronic if they have the same electron configurations. Which of the following atoms is isoelectronic to Cs+ (see periodic table here: https://www.ptable.com/Images/periodic%20table.png)? (A) I- (B) Kr (C) Xe- (D) Ba3+
(A) I- Looking at the periodic table, Cs+ must have the same electron configuration as uncharged Xe. The only other option with the [Xe] electron configuration is I-.
