ACS Advanced General Chemistry
Examination Questions and Correct
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Rationales 2026 Q&A | Instant
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Question 1
The atomic number of an element is equal to the number of:
A. Neutrons
B. Electrons and neutrons
C. Protons
D. Nucleons
Answer: C. Protons
Rationale: The atomic number uniquely identifies an element and is equal to the
number of protons in its nucleus.
Question 2
Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Alpha particle
,D. Electron
Answer: D. Electron
Rationale: Electrons carry a -1 charge and occupy orbitals surrounding the
nucleus.
Question 3
The mass number of an atom is the sum of:
A. Protons and electrons
B. Electrons and neutrons
C. Electrons only
D. Protons and neutrons
Answer: D. Protons and neutrons
Rationale: The mass number represents the total number of nucleons in the
nucleus.
Question 4
Isotopes of the same element differ in the number of:
A. Protons
B. Electrons
C. Valence electrons
D. Neutrons
Answer: D. Neutrons
Rationale: Isotopes have the same number of protons but different numbers of
neutrons.
,Question 5
Which orbital can hold a maximum of two electrons?
A. Any orbital
B. Only p orbitals
C. Only d orbitals
D. Any single orbital
Answer: D. Any single orbital
Rationale: According to the Pauli Exclusion Principle, each orbital can hold a
maximum of two electrons with opposite spins.
Question 6
The shape of an s orbital is:
A. Dumbbell
B. Cloverleaf
C. Torus
D. Spherical
Answer: D. Spherical
Rationale: All s orbitals have spherical symmetry around the nucleus.
Question 7
A p subshell contains how many orbitals?
A. 1
B. 2
C. 3
D. 5
, Answer: C. 3
Rationale: A p subshell consists of three orbitals: pₓ, pᵧ, and p_z.
Question 8
Which principle states that electrons occupy the lowest-energy orbitals first?
A. Hund's Rule
B. Pauli Exclusion Principle
C. Heisenberg Uncertainty Principle
D. Aufbau Principle
Answer: D. Aufbau Principle
Rationale: The Aufbau Principle describes the order in which electrons fill orbitals.
Question 9
Hund's Rule states that electrons occupy orbitals of equal energy:
A. In pairs first
B. Randomly
C. With opposite spins only
D. Singly before pairing
Answer: D. Singly before pairing
Rationale: Electrons maximize unpaired spins in degenerate orbitals before
pairing.
Question 10
The maximum number of electrons in the n = 2 energy level is:
A. 2
Examination Questions and Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
Question 1
The atomic number of an element is equal to the number of:
A. Neutrons
B. Electrons and neutrons
C. Protons
D. Nucleons
Answer: C. Protons
Rationale: The atomic number uniquely identifies an element and is equal to the
number of protons in its nucleus.
Question 2
Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Alpha particle
,D. Electron
Answer: D. Electron
Rationale: Electrons carry a -1 charge and occupy orbitals surrounding the
nucleus.
Question 3
The mass number of an atom is the sum of:
A. Protons and electrons
B. Electrons and neutrons
C. Electrons only
D. Protons and neutrons
Answer: D. Protons and neutrons
Rationale: The mass number represents the total number of nucleons in the
nucleus.
Question 4
Isotopes of the same element differ in the number of:
A. Protons
B. Electrons
C. Valence electrons
D. Neutrons
Answer: D. Neutrons
Rationale: Isotopes have the same number of protons but different numbers of
neutrons.
,Question 5
Which orbital can hold a maximum of two electrons?
A. Any orbital
B. Only p orbitals
C. Only d orbitals
D. Any single orbital
Answer: D. Any single orbital
Rationale: According to the Pauli Exclusion Principle, each orbital can hold a
maximum of two electrons with opposite spins.
Question 6
The shape of an s orbital is:
A. Dumbbell
B. Cloverleaf
C. Torus
D. Spherical
Answer: D. Spherical
Rationale: All s orbitals have spherical symmetry around the nucleus.
Question 7
A p subshell contains how many orbitals?
A. 1
B. 2
C. 3
D. 5
, Answer: C. 3
Rationale: A p subshell consists of three orbitals: pₓ, pᵧ, and p_z.
Question 8
Which principle states that electrons occupy the lowest-energy orbitals first?
A. Hund's Rule
B. Pauli Exclusion Principle
C. Heisenberg Uncertainty Principle
D. Aufbau Principle
Answer: D. Aufbau Principle
Rationale: The Aufbau Principle describes the order in which electrons fill orbitals.
Question 9
Hund's Rule states that electrons occupy orbitals of equal energy:
A. In pairs first
B. Randomly
C. With opposite spins only
D. Singly before pairing
Answer: D. Singly before pairing
Rationale: Electrons maximize unpaired spins in degenerate orbitals before
pairing.
Question 10
The maximum number of electrons in the n = 2 energy level is:
A. 2
