Q: A sodium street lamp emits light at a wavelength of $$589\ \mathrm{nm}. $$What is the frequency of this light? ($$c = 3.00 \times 10^8$\ \mathrm{m/s})$$

$$5.09 \times 10$$^{14}$$\ \mathrm{Hz}$$

Question 1

Which of the following statements best explains why the photoelectric effect could not be explained by classical wave theory?

Accepted Answer

Classical wave theory predicted that increasing the intensity of light would always eject electrons, regardless of frequency.

Question 2

Which equation correctly relates the wavelength ($$\lambda$$), frequency ($$
u$$), and speed of light ($$c) $$for electromagnetic radiation?

Accepted Answer

$$c = \lambda 
u$$

Question 3

A sodium street lamp emits light at a wavelength of $$589\ \mathrm{nm}. $$What is the frequency of this light? ($$c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$5.09 	imes 10$$^{14}$$\ \mathrm{Hz}$$

Question 4

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Question 5

According to the Bohr model, what happens when an electron in a hydrogen atom transitions from $$n=4 to$$ $$n=2$$?

Accepted Answer

A photon is emitted with energy equal to the difference between the two energy levels.

Question 6

Which of the following sets 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 7

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 8

Which of the following best describes Hund’s Rule?

Accepted Answer

Electrons fill degenerate orbitals singly with parallel spins before pairing.

Question 9

Which of the following electron configurations represents a transition metal in its ground state?

Accepted Answer

$$[\mathrm{Ar}]\ 4s^2$\ 3d^6$

Question 10

Which of the following statements about the hydrogen atom is TRUE according to quantum mechanics?

Accepted Answer

All orbitals with the same principal quantum number $$n$$ have the same energy.

Question 11

Which of the following is a correct condensed electron configuration for phosphorus (atomic number 15)?

Accepted Answer

$$[\mathrm{Ne}]\ 3s^2$\ 3p^3$

Question 12

Which quantum number is associated with the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number ($$m_l)$$

Question 13

Which of the following best describes the difference between core and valence electrons?

Accepted Answer

Core electrons are those in filled inner shells, while valence electrons are in the outermost shell.

Question 14

Which of the following elements is filling the 4f sublevel in its ground state electron configuration?

Accepted Answer

Europium (Eu)

Question 15

Which of the following is a limitation of the Bohr model of the atom?

Accepted Answer

It only accurately describes the hydrogen atom.

Question 16

Which equation expresses the de Broglie wavelength ($$\lambda) of a $$particle with mass $$m$$ and velocity $$v$$?

Accepted Answer

$$\lambda = \frac{h}{mv}$$

Question 17

Which of the following best describes the Heisenberg Uncertainty Principle?

Accepted Answer

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

Question 18

Which of the following electron configurations is an example of an anomaly due to half-filled d orbitals?

Accepted Answer

$$[\mathrm{Ar}]\ 4s^1$\ 3d^5$

Question 19

How many electrons can occupy all the orbitals with $$n=3 in a $$single atom?

Accepted Answer

18

Electronic Structure of Atoms: Quantum Mechanics and Atomic Orbitals

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