Q: A photon of blue light has a wavelength of $$473\ \text{nm}. $$What is its frequency ($$v$$)? Use $$c = 2.998 \times 10^8$\ \text{m/s}.$$

$$v = 4.23 \times 10$$^{14}$$\ \text{Hz}$$

Question 1

Which of the following phenomena could NOT be explained by classical physics at the turn of the 20th century, leading to the development of quantum theory?

Accepted Answer

Blackbody radiation

Question 2

According to Planck’s quantum hypothesis, what is the energy of a photon with frequency $$v$$?

Accepted Answer

$$E = h v$$

Question 3

A photon of blue light has a wavelength of $$473\ 	ext{nm}. $$What is its frequency ($$v$$)? Use $$c = 2.998 	imes 10^8$\ 	ext{m/s}.$$

Accepted Answer

$$v = 4.23 	imes 10$$^{14}$$\ 	ext{Hz}$$

Question 4

Which statement about the photoelectric effect is TRUE?

Accepted Answer

Electrons are emitted only if the light has a frequency above a threshold value.

Question 5

Calculate the energy (in kJ/mol) of a photon emitted when an electron in a hydrogen atom transitions from $$n=3 to$$ $$n=2. $$Use $$R_y = 2.179 	imes 10$$^{-18}$$\ 	ext{J}.$$

Accepted Answer

$$E = 457\ 	ext{kJ/mol}$$

Question 6

Which transition in a hydrogen atom emits a photon with the greatest wavelength?

Accepted Answer

$$n=4 to$$ $$n=3$$

Question 7

Which quantum number set corresponds to a 3p orbital?

Accepted Answer

$$n=3,\ l=1,\ m_l=0$$

Question 8

Which principle states that no two electrons in an atom can have the same set of four quantum numbers?

Accepted Answer

Pauli exclusion principle

Question 9

What is the condensed electron configuration for chlorine?

Accepted Answer

$$[Ne]3s^2$ 3p^5$

Question 10

Which element has the electron configuration $$[Ar]4s^2$ 3d$$^{10}$$ 4p^5$?

Accepted Answer

Bromine (Br)

Question 11

According to de Broglie, what is the wavelength ($$\lambda) of a $$particle of mass $$m$$ moving at velocity $$u$$?

Accepted Answer

$$\lambda = h / (m u)$$

Question 12

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

Accepted Answer

Magnetic quantum number ($$m_l)$$

Question 13

Which rule states that degenerate orbitals are occupied singly first and with parallel spins?

Accepted Answer

Hund's rule

Question 14

Which of the following is NOT a valid set of quantum numbers for an orbital?

Accepted Answer

$$n=2,\ l=2,\ m_l=0$$

Question 15

Which statement best describes the Heisenberg uncertainty principle?

Accepted Answer

It is impossible to know both the exact position and momentum of a subatomic particle simultaneously.

Question 16

Which orbital has the greatest penetration towards the nucleus?

Accepted Answer

1s

Question 17

Which of the following electron configurations represents an excited state for carbon?

Accepted Answer

$$1s^2$$ $$2s^1$$ $$2p^3$$

Question 18

Which scientist proposed that electrons move in fixed orbits around the nucleus and only certain energy levels are allowed?

Accepted Answer

Niels Bohr

Question 19

What is the main limitation of Bohr’s atomic model?

Accepted Answer

It cannot explain the spectra of multi-electron atoms.

Question 20

Which quantum number is associated with the shape of an orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Quantum-Mechanical Model of the Atom: Electromagnetic Radiation and Historical Context

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