Q: A green laser pointer emits light at a wavelength of $$515\ \mathrm{nm}. $$What is the frequency of this light? $$(c = 3.00 \times 10^8$\ \mathrm{m/s})$$

$$5.83 \times 10$$^{14}$$\ \mathrm{Hz}$$

Q: What is the energy (in joules) of a single photon of X-ray light with a wavelength of $$1.00 \times 10$$^{-10}$$\ \mathrm{m}$$? $$(h = 6.626 \times 10$$^{-34}$$\ \mathrm{J \cdot s},\ c = 3.00 \times 10^8$\ \mathrm{m/s})$$

$$1.99 \times 10$$^{-16}$$\ \mathrm{J}$$

Question 1

Which of the following best describes the concept of wave-particle duality as it applies to electrons?

Accepted Answer

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

Question 2

A sodium metal surface requires a minimum energy of $$4.41 	imes 10$$^{-19}$$\ \mathrm{J} to $$eject an electron via the photoelectric effect. What is the longest wavelength of light (in nm) that can cause electron emission from sodium? $$(h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J \cdot s},\ c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$450\ \mathrm{nm}$$

Question 3

Which experiment provided direct evidence for the wave nature of electrons?

Accepted Answer

The double-slit electron diffraction experiment

Question 4

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 and size of the orbital

Question 5

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

Accepted Answer

$$5.83 	imes 10$$^{14}$$\ \mathrm{Hz}$$

Question 6

Which of the following statements about the photoelectric effect is TRUE?

Accepted Answer

Electrons are emitted only if the frequency of the incident light is above a certain threshold, regardless of intensity.

Question 7

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 8

What is the energy (in joules) of a single photon of X-ray light with a wavelength of $$1.00 	imes 10$$^{-10}$$\ \mathrm{m}$$? $$(h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J \cdot s},\ c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$1.99 	imes 10$$^{-16}$$\ \mathrm{J}$$

Question 9

Which of the following best explains why high-energy electromagnetic radiation (such as gamma rays) is considered ionizing?

Accepted Answer

It has enough energy per photon to remove electrons from atoms or molecules.

Question 10

According to the Heisenberg uncertainty principle, which of the following statements is correct?

Accepted Answer

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

Question 11

How many d orbitals are present in the $$n=4$$ principal energy level?

Accepted Answer

5

Question 12

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number $$l$$

Question 13

An electron in a hydrogen atom transitions from $$n=5 to$$ $$n=2. $$Which of the following statements is TRUE?

Accepted Answer

The electron emits a photon whose energy equals the difference between the two energy levels.

Question 14

What is the de Broglie wavelength (in meters) of an electron moving at $$2.00 	imes 10^6$\ \mathrm{m/s}$$? $$(m_e = 9.11 	imes 10$$^{-31}$$\ \mathrm{kg},\ h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J \cdot s})$$

Accepted Answer

$$3.64 	imes 10$$^{-10}$$\ \mathrm{m}$$

Question 15

Which of the following best describes the difference between constructive and destructive interference?

Accepted Answer

Constructive interference results in a larger amplitude, destructive results in cancellation.

Question 16

Which of the following statements about atomic orbitals is FALSE?

Accepted Answer

All $$p$$ orbitals are spherical in shape.

Question 17

Which transition in a hydrogen atom would emit a photon with the highest energy?

Accepted Answer

$$n=2 to$$ $$n=1$$

Question 18

What is the total number of orbitals in the $$n=3$$ principal energy level?

Accepted Answer

9

Question 19

Which of the following best explains why the Bohr model could not explain the spectra of multi-electron atoms?

Accepted Answer

It could not explain the wave nature of electrons.

Quantum Mechanical Model of the Atom: Structure and Properties

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