Q: A photon has a wavelength of $$4.00 \times 10$$^{-7}$$\ \mathrm{m}. $$What is its energy? (Use $$h = 6.626 \times 10$$^{-34}$$\ \mathrm{J\cdot s}$$ and $$c = 3.00 \times 10^8$\ \mathrm{m/s})$$

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

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

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

Question 1

Which of the following electron configurations represents a ground-state atom of sulfur (S, atomic number 16)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^4$$

Question 2

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 3

Which element would you expect to have the highest first ionization energy?

Accepted Answer

Neon (Ne)

Question 4

A photon has a wavelength of $$4.00 	imes 10$$^{-7}$$\ \mathrm{m}. $$What is its energy? (Use $$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s}$$ and $$c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

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

Question 5

Which of the following statements best explains why atomic radius decreases across a period from left to right?

Accepted Answer

The effective nuclear charge increases, pulling electrons closer to the nucleus.

Question 6

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

Accepted Answer

$$n=4 to$$ $$n=1$$

Question 7

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

Accepted Answer

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

Question 8

Which of the following correctly lists the electromagnetic spectrum in order of increasing energy?

Accepted Answer

Radio waves, infrared, visible, ultraviolet, X-rays

Question 9

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number ($$l)$$

Question 10

Which of the following ions has the same electron configuration as argon ($$\mathrm{Ar}$$)?

Accepted Answer

$$\mathrm{Cl}^-$$

Question 11

Which of the following best describes the relationship between wavelength ($$\lambda) $$and frequency ($$
u) $$for electromagnetic radiation?

Accepted Answer

$$c = \lambda 
u$$

Question 12

Which of the following elements has the largest atomic radius?

Accepted Answer

Potassium (K)

Question 13

A hospital uses ultraviolet light to sterilize equipment. Which property of ultraviolet light makes it effective for this purpose?

Accepted Answer

It has enough energy to break chemical bonds in microorganisms.

Question 14

Which of the following is the correct set of quantum numbers for the last electron added to a phosphorus atom ($$Z=15) in $$its ground state?

Accepted Answer

$$n=3,\ l=1,\ m_l=1,\ m_s=+\frac{1}{2}$$

Question 15

Which of the following best explains why the $$4s$$ orbital is filled before the $$3d$$ orbital in the electron configuration of potassium?

Accepted Answer

The $$4s$$ orbital is lower in energy than the $$3d$$ orbital.

Question 16

Which of the following statements about the electromagnetic spectrum is correct?

Accepted Answer

Gamma rays have the shortest wavelength and highest frequency.

Question 17

A green laser pointer emits light at $$532\ \mathrm{nm}. $$Calculate the energy of one photon emitted by this laser. ($$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s}$$, $$c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$3.74 	imes 10$$^{-19}$$\ \mathrm{J}$$

Question 18

Which of the following is a correct statement about the periodic trend in ionization energy?

Accepted Answer

Ionization energy increases across a period and decreases down a group.

Question 19

Which of the following best describes Hund's rule as it applies to electron configuration?

Accepted Answer

Electrons fill degenerate orbitals singly before pairing.

Question 20

Which of the following transitions in the hydrogen atom corresponds to the absorption of the least energy?

Accepted Answer

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

Quantum Mechanics, Electron Configurations, and Periodic Trends: Study Guide

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