Q: A photon of light has a wavelength of $$ \lambda = 400 \ \mathrm{nm} . $$What is the energy of this photon? (Use $$ h = 6.626 \times 10$$^{-34}$$ \ \mathrm{J \cdot s} $$, $$ c = 3.00 \times 10^8$ \ \mathrm{m/s} )$$

$$ 4.97 \times 10$$^{-19}$$ \ \mathrm{J} $$

Q: Calculate the energy required to remove an electron from a metal with a work function $$ \phi = 2.50 \ \mathrm{eV} $$ using light of wavelength $$ 350 \ \mathrm{nm} . (1 eV$$ = $$ 1.602 \times 10$$^{-19}$$ \ \mathrm{J} )$$

$$ 3.55 \times 10$$^{-19}$$ \ \mathrm{J} $$

Question 1

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

Accepted Answer

Electrons can exhibit both wave-like and particle-like properties depending on the experiment.

Question 2

A photon of light has a wavelength of $$ \lambda = 400 \ \mathrm{nm} . $$What is the energy of this photon? (Use $$ h = 6.626 	imes 10$$^{-34}$$ \ \mathrm{J \cdot s} $$, $$ c = 3.00 	imes 10^8$ \ \mathrm{m/s} )$$

Accepted Answer

$$ 4.97 	imes 10$$^{-19}$$ \ \mathrm{J} $$

Question 3

Which of the following correctly ranks electromagnetic radiation from lowest to highest energy per photon?

Accepted Answer

Radio \u003c Infrared \u003c Visible \u003c Ultraviolet \u003c X-rays

Question 4

The frequency $$ 
u  of a $$photon is related to its wavelength $$ \lambda  by $$which of the following equations?

Accepted Answer

$$ 
u = \dfrac{c}{\lambda} $$

Question 5

In the photoelectric effect, which of the following statements is true?

Accepted Answer

Electrons are emitted from a metal surface only if the incident light has a frequency above a certain threshold.

Question 6

Calculate the energy required to remove an electron from a metal with a work function $$ \phi = 2.50 \ \mathrm{eV} $$ using light of wavelength $$ 350 \ \mathrm{nm} . (1 eV$$ = $$ 1.602 	imes 10$$^{-19}$$ \ \mathrm{J} )$$

Accepted Answer

$$ 3.55 	imes 10$$^{-19}$$ \ \mathrm{J} $$

Question 7

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number $$ l $$

Question 8

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

Accepted Answer

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

Question 9

Which of the following best explains why atomic emission spectra are discrete rather than continuous?

Accepted Answer

Electrons in atoms can only occupy specific energy levels, so only certain photon energies are emitted.

Question 10

A sodium street lamp emits yellow light at $$ 589 \ \mathrm{nm} . $$How many photons are emitted per second if the lamp emits $$ 40.0 \ \mathrm{J}  of $$energy per second at this wavelength?

Accepted Answer

$$ 1.19 	imes 10$$^{20}$$ $$

Question 11

Which of the following transitions in the hydrogen atom would emit the highest energy photon?

Accepted Answer

$$ n = 3 \rightarrow n = 1 $$

Question 12

Which statement about the principal quantum number $$ n  is $$correct?

Accepted Answer

It determines the overall size and energy of an orbital.

Question 13

If an electron in a hydrogen atom absorbs a photon and moves from $$ n = 1  to$$ $$ n = 3 $$, what happens to the energy of the atom?

Accepted Answer

The atom's energy increases by the energy of the absorbed photon.

Question 14

Which of the following best describes the difference between emission and absorption spectra?

Accepted Answer

Emission spectra show light emitted at specific wavelengths, while absorption spectra show dark lines where light is absorbed.

Question 15

Which quantum number is responsible for the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number $$ m_l $$

Question 16

A certain metal has a work function of $$ 4.0 \ \mathrm{eV} . $$What is the minimum frequency of light required to eject electrons from this metal? ($$ h = 6.626 	imes 10$$^{-34}$$ \ \mathrm{J \cdot s} $$, $$ 1 \ \mathrm{eV} = 1.602 	imes 10$$^{-19}$$ \ \mathrm{J} )$$

Accepted Answer

$$ 9.67 	imes 10$$^{14}$$ \ \mathrm{Hz} $$

Question 17

Which of the following statements about the quantum mechanical model of the atom is correct?

Accepted Answer

It describes the probability of finding an electron in a particular region of space.

Question 18

Which of the following is a valid set of quantum numbers for an electron in a 3d orbital?

Accepted Answer

$$ n = 3, \ l = 2, \ m_l = 1, \ m_s = -\dfrac{1}{2} $$

Question 19

Which of the following best explains why the energy difference between atomic energy levels decreases as $$ n $$ increases?

Accepted Answer

The energy levels get closer together as $$ n $$ increases because the electron is farther from the nucleus and less tightly bound.

Quantum Mechanical Model of the Atom – Study Notes

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