Learning
Here are 100 original NCLEX-style practice questions for CHEM 103 Module 2.
They focus on atomic structure, electron configuration, periodic trends,
chemical bonding, molecular geometry, polarity, and intermolecular forces,
with clinical and physiological applications. These are original practice items
and are not official exam questions.
Question 1:
A nurse is teaching a client about the importance of electrolytes. Which
statement best explains why sodium ions (Na⁺) are attracted to chloride ions
(Cl⁻) in the body?
A. They share electrons equally.
B. They have opposite charges and form ionic bonds.
C. They form hydrogen bonds with water.
D. They have similar electronegativities.
Correct answer: B
Rationale:
Na⁺ is a cation and Cl⁻ is an anion. Opposite charges attract, forming an ionic
bond. In solution, these ions are surrounded by water molecules, but the initial
attraction is electrostatic.
Question 2:
A client is diagnosed with hyponatremia. Which principle best explains the
movement of water in this condition?
A. Water moves from areas of high solute concentration to low solute
concentration. B. Water moves from areas of low solute concentration to high
solute concentration.
C. Sodium moves into cells to equalize concentration.
D. Chloride shifts out of cells to balance charge.
Correct answer: B
,Rationale:
Water follows osmosis: it moves toward higher solute concentration. In
hyponatremia, low serum sodium makes the extracellular fluid hypotonic
relative to intracellular fluid, so water moves into cells, causing swelling.
Question 3:
Which subatomic particle determines the atomic number of an element?
A. Neutron
B. Electron
C. Proton
D. Positron
Correct answer: C
Rationale:
The atomic number equals the number of protons in the nucleus. It defines the
element.
Question 4:
An atom has 12 protons, 12 neutrons, and 12 electrons. What is its mass
number?
A. 12
B. 24
C. 36
D. 0
Correct answer: B
Rationale:
Mass number = protons + neutrons = 12 + 12 = 24.
Question 5:
A client is given a radioactive isotope for a diagnostic scan. Which statement
about isotopes is correct?
,A. Isotopes have different numbers of protons.
B. Isotopes have different numbers of electrons.
C. Isotopes have different numbers of neutrons.
D. Isotopes have different atomic numbers.
Correct answer: C
Rationale:
Isotopes of an element have the same number of protons but different
numbers of neutrons.
Question 6:
Which electron configuration represents a neutral oxygen atom (atomic
number 8)?
A. 1s² 2s² 2p⁴
B. 1s² 2s² 2p⁶
C. 1s² 2s² 2p²
D. 1s² 2s² 2p⁵ Correct answer: A
Rationale:
Oxygen has 8 electrons: 1s² 2s² 2p⁴.
Question 7:
How many valence electrons does a neutral chlorine atom (atomic number 17)
have?
A. 1
B. 5
C. 7
D. 8
Correct answer: C
Rationale:
Chlorine is in Group 17, so it has 7 valence electrons.
, Question 8:
A nurse is explaining why potassium (K⁺) is critical for nerve conduction. Which
property allows K⁺ to move across cell membranes?
A. It is a large cation.
B. It is a small, positively charged ion.
C. It forms covalent bonds with proteins.
D. It is lipid-soluble.
Correct answer: B
Rationale:
K⁺ is a small, positively charged ion that can move through ion channels down
its electrochemical gradient, essential for action potentials.
Question 9:
Which periodic trend explains why fluorine is more electronegative than
lithium?
A. Atomic radius increases across a period.
B. Electronegativity increases across a period.
C. Ionization energy decreases across a period.
D. Metallic character increases across a period.
Correct answer: B
Rationale:
Electronegativity generally increases from left to right across a period due to
increasing nuclear charge and decreasing atomic radius.
Question 10:
A client has a low serum calcium level. Which type of bond is most important
for calcium's role in bone structure?
A. Covalent bond
B. Ionic bond
C. Hydrogen bond