Question 1

Which of the following best describes the wave–particle duality of the electron?

Accepted Answer

Electrons exhibit both particle-like and wave-like properties depending on the experimental conditions.

Question 2

According to the quantum mechanical model, what does the principal quantum number $n$ primarily determine for an electron in an atom?

Accepted Answer

The energy level and size of the orbital

Question 3

A sodium metal surface requires $2.28 	imes 10^5$ J/mol to dislodge electrons via the photoelectric effect. What is the minimum wavelength (in nm) of light that can cause this effect? (Use $h = 6.626 	imes 10^{-34}$ J·s, $c = 3.00 	imes 10^8$ m/s, $N_A = 6.022 	imes 10^{23}$ mol$^{-1}$)

Accepted Answer

$524$ nm

Question 4

Which of the following statements about the Heisenberg Uncertainty Principle is correct?

Accepted Answer

The more precisely we know the position of an electron, the less precisely we can know its velocity.

Question 5

A green laser pointer emits light with a wavelength of $515$ nm. What is the frequency of this light? (Use $c = 3.00 	imes 10^8$ m/s)

Accepted Answer

$5.83 	imes 10^{14}$ Hz

Question 6

Which quantum number(s) determine the number of orbitals in a given subshell?

Accepted Answer

The angular momentum quantum number $l$ and the magnetic quantum number $m_l$

Question 7

Which phenomenon provides direct evidence for the wave nature of electrons?

Accepted Answer

The diffraction pattern produced when electrons pass through a crystal

Question 8

What is the energy (in Joules) of a single photon of red light with a wavelength of $700$ nm? (Use $h = 6.626 	imes 10^{-34}$ J·s, $c = 3.00 	imes 10^8$ m/s)

Accepted Answer

$2.84 	imes 10^{-19}$ J

Question 9

Which of the following best explains why ultraviolet light can eject electrons from a metal surface when yellow light cannot?

Accepted Answer

Ultraviolet light has a higher frequency and therefore more energy per photon than yellow light.

Question 10

How many orbitals are present in the $n = 3$ principal energy level of an atom?

Accepted Answer

9

Question 11

Which set of quantum numbers is NOT allowed for an electron in an atom?

Accepted Answer

$n = 2,\ l = 2,\ m_l = 0,\ m_s = +\frac{1}{2}$

Question 12

According to de Broglie’s hypothesis, what is the wavelength (in meters) of an electron (mass $9.11 	imes 10^{-31}$ kg) moving at $6.1 	imes 10^6$ m/s? (Use $h = 6.626 	imes 10^{-34}$ J·s)

Accepted Answer

$1.19 	imes 10^{-10}$ m

Question 13

Which of the following statements about atomic emission spectra is correct?

Accepted Answer

Each line in the emission spectrum corresponds to a transition between specific energy levels of electrons.

Question 14

What is the maximum number of electrons that can occupy the $3d$ subshell?

Accepted Answer

10

Question 15

Which quantum number describes the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number $m_l$

Question 16

A photon with energy greater than the binding energy of an electron in a metal causes the electron to be ejected. What happens to the excess energy?

Accepted Answer

It becomes the kinetic energy of the ejected electron.

Question 17

Which of the following best describes the shape of a $p$ orbital?

Accepted Answer

Dumbbell-shaped (two lobes)

Question 18

If an electron in a hydrogen atom transitions from $n=5$ to $n=2$, what happens?

Accepted Answer

A photon is emitted and the atom relaxes to a lower energy state.

Question 19

Which of the following is a consequence of the indeterminacy of electron behavior in atoms?

Accepted Answer

We can only describe the probability of finding an electron in a particular region.

Quantum Mechanics: The Quantum Mechanical Model of the Atom

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