Q: Red light has a wavelength of $$725\ \mathrm{nm}. $$What is its frequency ($$\nu$$)? Use $$c = 3.00 \times 10^8$\ \mathrm{m/s}.$$

$$4.14 \times 10$$^{14}$$\ \mathrm{Hz}$$

Q: X-rays have a frequency of $$1 \times 10$$^{18}$$\ \mathrm{s}^{-1}. $$What is their wavelength?

$$3.00 \times 10$$^{-10}$$\ \mathrm{m}$$

Q: Calculate the energy of a photon with a frequency of $$5.09 \times 10$$^{14}$$\ \mathrm{s}^{-1}$$. ($$h = 6.626 \times 10$$^{-34}$$\ \mathrm{J\cdot s})$$

$$3.37 \times 10$$^{-19}$$\ \mathrm{J}$$

Q: Using de Broglie’s equation, $$\lambda = \dfrac{h}{mv}$$, what is the wavelength of an electron ($$m = 9.11 \times 10$$^{-31}$$\ \mathrm{kg}) $$moving at $$3.00 \times 10^6$\ \mathrm{m/s}$$? ($$h = 6.626 \times 10$$^{-34}$$\ \mathrm{J\cdot s})$$

$$2.43 \times 10$$^{-10}$$\ \mathrm{m}$$

Question 1

Which of the following best defines the wavelength ($$\lambda) of $$electromagnetic radiation?

Accepted Answer

The distance between two consecutive peaks or troughs in a wave.

Question 2

Red light has a wavelength of $$725\ \mathrm{nm}. $$What is its frequency ($$
u$$)? Use $$c = 3.00 	imes 10^8$\ \mathrm{m/s}.$$

Accepted Answer

$$4.14 	imes 10$$^{14}$$\ \mathrm{Hz}$$

Question 3

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

Accepted Answer

$$c = \lambda 
u$$

Question 4

X-rays have a frequency of $$1 	imes 10$$^{18}$$\ \mathrm{s}^{-1}. $$What is their wavelength?

Accepted Answer

$$3.00 	imes 10$$^{-10}$$\ \mathrm{m}$$

Question 5

Which statement best describes the photoelectric effect?

Accepted Answer

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

Question 6

Calculate the energy of a photon with a frequency of $$5.09 	imes 10$$^{14}$$\ \mathrm{s}^{-1}$$. ($$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s})$$

Accepted Answer

$$3.37 	imes 10$$^{-19}$$\ \mathrm{J}$$

Question 7

According to Bohr’s model, what happens when an electron in a hydrogen atom transitions from $$n=5 to$$ $$n=3$$?

Accepted Answer

A photon is emitted and the atom loses energy.

Question 8

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

Accepted Answer

It cannot explain the spectra of atoms with more than one electron.

Question 9

Using de Broglie’s equation, $$\lambda = \dfrac{h}{mv}$$, what is the wavelength of an electron ($$m = 9.11 	imes 10$$^{-31}$$\ \mathrm{kg}) $$moving at $$3.00 	imes 10^6$\ \mathrm{m/s}$$? ($$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s})$$

Accepted Answer

$$2.43 	imes 10$$^{-10}$$\ \mathrm{m}$$

Question 10

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Question 11

How many electrons can occupy a single orbital, and what principle governs this?

Accepted Answer

2 electrons, Pauli Exclusion Principle

Question 12

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 13

Which of the following electron configurations represents a calcium ion ($$\mathrm{Ca}^{2+}$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^6$$

Question 14

Which orbital has the highest energy among the following: $$3s$$, $$3p$$, $$3d$$, $$4s$$?

Accepted Answer

$$3d$$

Question 15

How many unpaired electrons are present in a carbon atom ($$1s^2$$\ $$2s^2$$\ $$2p^2$$)?

Accepted Answer

2

Question 16

Which element has 7 valence electrons in the 5th energy level?

Accepted Answer

Iodine ($$\mathrm{I})$$

Question 17

Which rule states that electrons will fill degenerate orbitals singly before pairing up?

Accepted Answer

Hund's Rule

Question 18

Which principle explains why it is impossible to know both the exact position and momentum of an electron simultaneously?

Accepted Answer

Heisenberg Uncertainty Principle

Question 19

Which of the following best describes a valence electron?

Accepted Answer

An electron in the outermost energy level of an atom

Question 20

Which of the following statements about atomic orbitals is correct?

Accepted Answer

An orbital describes a region in space where there is a high probability of finding an electron.

Unit 6: Electronic Structure of Atoms – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards