AP Chemistry Examination Questions
and Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. What is the smallest unit of an element that retains the properties of that
element?
A. Molecule
B. Compound
C. Atom
D. Ion
Correct Answer: C. Atom
Rationale: An atom is the smallest unit of an element that maintains the chemical
properties of that element.
2. Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Nucleus
D. Electron
Correct Answer: D. Electron
Rationale: Electrons are negatively charged particles found outside the nucleus.
3. Which subatomic particle determines the identity of an element?
,A. Electron number
B. Neutron number
C. Proton number
D. Energy level number
Correct Answer: C. Proton number
Rationale: The number of protons, called the atomic number, identifies an
element.
4. The atomic number of an element represents the number of
A. Neutrons
B. Electrons and neutrons
C. Protons
D. Energy levels
Correct Answer: C. Protons
Rationale: Atomic number equals the number of protons in an atom's nucleus.
5. Isotopes of the same element differ in their number of
A. Protons
B. Electrons
C. Atomic charges
D. Neutrons
Correct Answer: D. Neutrons
Rationale: Isotopes have the same number of protons but different numbers of
neutrons.
6. The mass number of an atom equals the number of
A. Protons only
B. Electrons only
,C. Protons plus neutrons
D. Neutrons plus electrons
Correct Answer: C. Protons plus neutrons
Rationale: Mass number is the total number of particles in the nucleus: protons
and neutrons.
7. Which element is classified as a noble gas?
A. Sodium
B. Oxygen
C. Chlorine
D. Neon
Correct Answer: D. Neon
Rationale: Neon belongs to Group 18, the noble gases, which have stable electron
configurations.
8. Elements in the same group on the periodic table have similar
A. Atomic masses
B. Number of neutrons
C. Chemical properties
D. Physical states
Correct Answer: C. Chemical properties
Rationale: Elements in the same group have similar valence electron
arrangements, giving them similar chemical behavior.
9. Which element is an alkali metal?
A. Calcium
B. Aluminum
, C. Potassium
D. Chlorine
Correct Answer: C. Potassium
Rationale: Potassium is a Group 1 alkali metal.
10. What is the charge of a typical calcium ion?
A. +1
B. +2
C. -1
D. -2
Correct Answer: B. +2
Rationale: Calcium loses two electrons to form a Ca²⁺ ion.
11. Which type of bond involves the sharing of electrons?
A. Ionic bond
B. Metallic bond
C. Hydrogen bond
D. Covalent bond
Correct Answer: D. Covalent bond
Rationale: Covalent bonds form when atoms share electron pairs.
12. Ionic bonds typically form between
A. Two metals
B. Two nonmetals
C. A metal and a nonmetal
D. Two noble gases
Correct Answer: C. A metal and a nonmetal
and Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. What is the smallest unit of an element that retains the properties of that
element?
A. Molecule
B. Compound
C. Atom
D. Ion
Correct Answer: C. Atom
Rationale: An atom is the smallest unit of an element that maintains the chemical
properties of that element.
2. Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Nucleus
D. Electron
Correct Answer: D. Electron
Rationale: Electrons are negatively charged particles found outside the nucleus.
3. Which subatomic particle determines the identity of an element?
,A. Electron number
B. Neutron number
C. Proton number
D. Energy level number
Correct Answer: C. Proton number
Rationale: The number of protons, called the atomic number, identifies an
element.
4. The atomic number of an element represents the number of
A. Neutrons
B. Electrons and neutrons
C. Protons
D. Energy levels
Correct Answer: C. Protons
Rationale: Atomic number equals the number of protons in an atom's nucleus.
5. Isotopes of the same element differ in their number of
A. Protons
B. Electrons
C. Atomic charges
D. Neutrons
Correct Answer: D. Neutrons
Rationale: Isotopes have the same number of protons but different numbers of
neutrons.
6. The mass number of an atom equals the number of
A. Protons only
B. Electrons only
,C. Protons plus neutrons
D. Neutrons plus electrons
Correct Answer: C. Protons plus neutrons
Rationale: Mass number is the total number of particles in the nucleus: protons
and neutrons.
7. Which element is classified as a noble gas?
A. Sodium
B. Oxygen
C. Chlorine
D. Neon
Correct Answer: D. Neon
Rationale: Neon belongs to Group 18, the noble gases, which have stable electron
configurations.
8. Elements in the same group on the periodic table have similar
A. Atomic masses
B. Number of neutrons
C. Chemical properties
D. Physical states
Correct Answer: C. Chemical properties
Rationale: Elements in the same group have similar valence electron
arrangements, giving them similar chemical behavior.
9. Which element is an alkali metal?
A. Calcium
B. Aluminum
, C. Potassium
D. Chlorine
Correct Answer: C. Potassium
Rationale: Potassium is a Group 1 alkali metal.
10. What is the charge of a typical calcium ion?
A. +1
B. +2
C. -1
D. -2
Correct Answer: B. +2
Rationale: Calcium loses two electrons to form a Ca²⁺ ion.
11. Which type of bond involves the sharing of electrons?
A. Ionic bond
B. Metallic bond
C. Hydrogen bond
D. Covalent bond
Correct Answer: D. Covalent bond
Rationale: Covalent bonds form when atoms share electron pairs.
12. Ionic bonds typically form between
A. Two metals
B. Two nonmetals
C. A metal and a nonmetal
D. Two noble gases
Correct Answer: C. A metal and a nonmetal
