AP Chemistry Exam Unit 1 Practice Test ( Atomic Structure and Properties)

Last Updated on January 10, 2025

AP Chemistry Exam Unit 1 Practice Test (Atomic Structure and Properties). Try our free AP Chemistry Unit 1: Atomic Structure and Properties Multiple Choice Questions and Answers and Free-Response Questions for the Advanced Placement (AP) Exam.

These practice test quizzes feature a variety of question-and-answer sets. This online quiz enhances your exam prep by providing accessible and engaging subject reviews, covering topics from Moles and molar mass to Valence electrons and ionic compounds.

Table of Contents

AP Chemistry Exam Unit 1 Practice Test 2025

AP Chemistry Unit 1: Atomic Structure and Properties

AP Chemistry Practice Test
Unit 1: Atomic Structure and Properties
Total Items: 25 (Multiple Choice Questions)

Unit 1: Atomic Structure and Properties

You’ll learn about the composition of atoms and ways scientists measure and categorize these building blocks of matter.

Topics may include:

Moles and molar mass
Mass spectra of elements
Elemental composition of pure substances
Composition of mixtures
Atomic structure and electron configuration
Photoelectron spectroscopy
Periodic trends
Valence electrons and ionic compounds

On The Exam

7%–9% of exam score

1 / 25

Which of the following shows the valence electrons of an uncharged atom of Sb?

(A)

(B)

(C)

(D)

2 / 25

Which of the following elements has the greatest number of p electrons?

(A) Arsenic since it has the highest atomic number and so the others can’t have more

(B) Silicon since it is alphabetically last in this group

(D) Chlorine since it has 5 p electrons in its period

3 / 25

What is the wavelength of light that has a frequency of 4.00 × 10¹⁴ s^–1? (The speed of light is 3.00 × 10⁸ m s^–1.)

(A) 7.5 nm because this is the result of speed divided by frequency

(B) 1,333 nm because this is the result of frequency divided by speed

(D) 1.33 cm–1 since the speed of light should have units of cm/s

4 / 25

Which electromagnetic wave has the highest energy? The x-axis is time, and the y-axis is amplitude.

(A) Wave A

(B) Wave B

(D) Wave D

5 / 25

What is the complete electron configuration for silicon?

(A) [Ne] 3s² 3p²

(B) 1s² 2s² 2p⁶ 3s² 3p⁴

(D) 1s² 2s² 2p⁶ 3s² 3p²

6 / 25

Calcium can have an electron in an f orbital

(A) if the calcium is in the elemental state

(B) if the calcium is in an excited state

(D) if the calcium is a negative ion

7 / 25

Which of the following best depicts a p orbital?

(A)

(B)

(C)

(D)

8 / 25

The wave-particle duality of nature applies to only

(A) everything

(B) light because of its wave properties

(D) electrons because they determine the chemical nature of the elements

9 / 25

Which orbital diagram represents the outer electrons of the ground state of an element?

(A)

(B)

(C)

(D)

10 / 25

Albert Einstein was given the Nobel Prize for the discovery and explanation of the photoelectric effect. What is this effect?

(A) It is spectroscopy using visible light.

(B) It is the ejection of electrons from a surface by photons.

(D) It is another way of stating the Heisenberg uncertainty principle.

11 / 25

Which equation best expresses the energy of a photon?

E= 1/2 mv²

E = mc²

E = IR

E = hν

12 / 25

The valence electrons are

(A) all electrons in an atom beyond the preceding noble gas

(B) all outermost electrons in a sublevel

(D) electrons in the last unfilled sublevel

13 / 25

The f sublevel may contain a maximum of

(A) 14 electrons

(B) 10 electrons

(D) 2 electrons

14 / 25

Which of the following is FALSE?

(A) The 4d orbitals are in the fourth period of the periodic table.

(B) The 7s orbitals are in the seventh period of the periodic table.

(D) The 6s orbitals are spherical in shape

15 / 25

Millikan found the mass of an electron by finding the common factor in a mass of data. What is the common factor in the data presented?

1.18 × 10^–34 g

2.36 × 10^–34 g

4.72 × 10^–34 g

9.44 × 10^–34 g

16 / 25

You have just discovered a new, fundamental particle of nature. When measuring its mass, you obtain the following data for four samples:

4.72 × 10^–34 gram

9.44 × 10^–34 gram

1.18 × 10^–33 gram

1.65 × 10^–33 gram

17 / 25

Which quantum number describes the shape of an orbital?

(A) The principal quantum number, n

(B) ℓ, which is the second term in an electron configuration

(D) m_s, which is the spin quantum number

18 / 25

Which statement is correct?

(A) Technetium, Tc, has 15 p electrons.

(B) Argon has 18 valence electrons

(D) Tungsten has 14 f electrons

19 / 25

Which of the following principles is NOT part of Dalton’s atomic theory?

(A) Chemical reactions are simple rearrangements of atoms.

(B) Atoms follow the law of multiple proportions.

(D) All matter is composed of atoms.

20 / 25

Which was used to determine the charge of the electron?

(A) The gold foil experiment

(B) Deflection of cathode rays by electric and magnetic fields

(D) The mass spectrometer

21 / 25

What is the maximum number of valence electrons that any atom may possess?

(A) 32 is the maximum number of electrons because the s orbital can have 2 electrons, the p orbital can have 6 electrons, the d orbital can have 10 electrons, and the f orbital can have 14 electrons, which all add up to 32 electrons.

(B) 2 valence electrons are the most that an s orbital can contain.

(D) 2 s electrons and 6 p electrons add up to 8, which is the maximum number of valence electrons possible.

22 / 25

Which electronic transition requires the addition of the most energy?

(A) n = 1 to n = 3 because this has the largest energy increase

(B) n = 5 to n = 2 since this has the largest size decrease

(D) n = 4 to n = 1 because this has the largest momentum decrease

23 / 25

Which electronic configuration corresponds to that of a noble gas?

(A) 1s² 2s² 2p⁶ 3s² 3p⁶4s¹ because it has the most energy levels

(B) 1s² 2s² 2p⁶ 3s² 3p⁴ since it ends with s and p electrons

(D) 1s² 2s² 2p⁶ 3s¹ since it has the characteristic ns np structure of a noble gas

24 / 25

Which element has an electronic configuration that has the largest number of unpaired electrons?

(A) Fe because it is in the middle of the d block and has 4 unpaired electrons

(B) Al since it forms the Al³⁺ ion and has all unpaired electrons

(D) Ni since it has 2 unpaired electrons

25 / 25

How many protons, neutrons, and electrons does the neutral atom of the chromium-52 isotope have (also written as ⁵²Cr)?

(A) 52 p, 28 n, and 52 e^-

(B) 28 p, 24 n, and 24 e^-

(D) 24 p, 28 n, and 24 e^-

Your score is

Free-Response Question

Answer the following question concerning the structure of the atom, the use of light as a probe of atomic structure, and the development of the modern quantum mechanical view of the atom.

Describe the significant experiments that led to the discovery of the properties of the electron, proton, and neutron. Describe the results and the interpretation of results that contributed to development of the atomic model.
The bond energy of a carbon-carbon bond is approximately 350 kJ/mol. Explain why electromagnetic radiation with wavelengths shorter than those in the visible region of the spectrum is often called ionizing radiation.
Sketch an outline of the periodic table, and discuss how the four quantum numbers n, ℓ, mℓ, and ms relate to the periodic table.
If an electron drops from the fifth energy level to the second energy level in a hydrogen atom, will energy be released or absorbed? Will the energy of the electron increase or decrease? Explain your answers.