CHEM 121 Module 2 | Foundations of General Chemistry
w/Lab Exam Q&A | Portage Learning
These are original practice questions written for study. They cover common CHEM 121
Module 2 | Atoms, Molecules, and Ions topics: atomic theory, subatomic particles,
atomic number and mass number, isotopes, atomic mass, periodic table organization,
ions, ionic and molecular compounds, nomenclature, and chemical formulas, with
NCLEX-style clinical framing.
Question 1:
Which scientist proposed that all matter is composed of tiny indivisible particles called
atoms?
A. Dalton
B. Thomson
C. Rutherford
D. Bohr
Correct answer: A
Rationale: Dalton proposed the atomic theory, stating that all matter is made of atoms.
Question 2:
Which scientist discovered the electron using cathode ray tubes?
A. Dalton
B. Thomson
C. Rutherford
D. Bohr
Correct answer: B
Rationale: Thomson discovered the electron and proposed the plum pudding model.
Question 3:
Which scientist proposed the nuclear model of the atom based on the gold foil
experiment?
A. Dalton
B. Thomson
C. Rutherford
D. Bohr
,Correct answer: C
Rationale: Rutherford's gold foil experiment showed that the atom has a small, dense,
positively charged nucleus.
Question 4:
Which scientist proposed that electrons orbit the nucleus in fixed energy levels?
A. Dalton
B. Thomson
C. Rutherford
D. Bohr
Correct answer: D
Rationale: Bohr proposed quantized energy levels for electrons.
Question 5:
Which subatomic particle has a positive charge?
A. Electron
B. Neutron
C. Proton
D. Positron
Correct answer: C
Rationale: Protons are positively charged particles found in the nucleus.
Question 6:
Which subatomic particle has no charge?
A. Electron
B. Neutron
C. Proton
D. Ion
Correct answer: B
Rationale: Neutrons are neutral particles found in the nucleus.
Question 7:
Which subatomic particle has a negative charge?
A. Electron
B. Neutron
, C. Proton
D. Cation
Correct answer: A
Rationale: Electrons are negatively charged particles that orbit the nucleus.
Question 8:
Where is most of the mass of an atom concentrated?
A. Electron cloud
B. Nucleus
C. Orbitals
D. Valence shell
Correct answer: B
Rationale: The nucleus contains protons and neutrons, which account for nearly all
atomic mass.
Question 9:
The atomic number of an element is equal to the number of:
A. Neutrons
B. Protons
C. Electrons plus neutrons
D. Protons plus neutrons
Correct answer: B
Rationale: Atomic number (Z) equals the number of protons in the nucleus.
Question 10:
The mass number of an atom is equal to the number of:
A. Protons only
B. Neutrons only
C. Protons plus neutrons
D. Protons plus electrons
Correct answer: C
Rationale: Mass number (A) = protons + neutrons.
Question 11:
An atom with 11 protons, 12 neutrons, and 11 electrons has a mass number of:
w/Lab Exam Q&A | Portage Learning
These are original practice questions written for study. They cover common CHEM 121
Module 2 | Atoms, Molecules, and Ions topics: atomic theory, subatomic particles,
atomic number and mass number, isotopes, atomic mass, periodic table organization,
ions, ionic and molecular compounds, nomenclature, and chemical formulas, with
NCLEX-style clinical framing.
Question 1:
Which scientist proposed that all matter is composed of tiny indivisible particles called
atoms?
A. Dalton
B. Thomson
C. Rutherford
D. Bohr
Correct answer: A
Rationale: Dalton proposed the atomic theory, stating that all matter is made of atoms.
Question 2:
Which scientist discovered the electron using cathode ray tubes?
A. Dalton
B. Thomson
C. Rutherford
D. Bohr
Correct answer: B
Rationale: Thomson discovered the electron and proposed the plum pudding model.
Question 3:
Which scientist proposed the nuclear model of the atom based on the gold foil
experiment?
A. Dalton
B. Thomson
C. Rutherford
D. Bohr
,Correct answer: C
Rationale: Rutherford's gold foil experiment showed that the atom has a small, dense,
positively charged nucleus.
Question 4:
Which scientist proposed that electrons orbit the nucleus in fixed energy levels?
A. Dalton
B. Thomson
C. Rutherford
D. Bohr
Correct answer: D
Rationale: Bohr proposed quantized energy levels for electrons.
Question 5:
Which subatomic particle has a positive charge?
A. Electron
B. Neutron
C. Proton
D. Positron
Correct answer: C
Rationale: Protons are positively charged particles found in the nucleus.
Question 6:
Which subatomic particle has no charge?
A. Electron
B. Neutron
C. Proton
D. Ion
Correct answer: B
Rationale: Neutrons are neutral particles found in the nucleus.
Question 7:
Which subatomic particle has a negative charge?
A. Electron
B. Neutron
, C. Proton
D. Cation
Correct answer: A
Rationale: Electrons are negatively charged particles that orbit the nucleus.
Question 8:
Where is most of the mass of an atom concentrated?
A. Electron cloud
B. Nucleus
C. Orbitals
D. Valence shell
Correct answer: B
Rationale: The nucleus contains protons and neutrons, which account for nearly all
atomic mass.
Question 9:
The atomic number of an element is equal to the number of:
A. Neutrons
B. Protons
C. Electrons plus neutrons
D. Protons plus neutrons
Correct answer: B
Rationale: Atomic number (Z) equals the number of protons in the nucleus.
Question 10:
The mass number of an atom is equal to the number of:
A. Protons only
B. Neutrons only
C. Protons plus neutrons
D. Protons plus electrons
Correct answer: C
Rationale: Mass number (A) = protons + neutrons.
Question 11:
An atom with 11 protons, 12 neutrons, and 11 electrons has a mass number of:
