C785 Biochemistry Module 1: Fundamentals of Chemistry and Biology
2026 |WGU
1. Which subatomic particle is primarily responsible for determining the
chemical reactivity of an atom?
A. Proton
B. Electron
C. Neutron
D. Nucleus
Answer: B
Rationale: Electrons, specifically those in the outermost shell (valence electrons), interact
with other atoms to form chemical bonds, determining reactivity.
2. An atom with 6 protons, 6 neutrons, and 6 electrons has an atomic mass of
approximately:
A. 12 amu
B. 6 amu
C. 18 amu
D. 0 amu
Answer: A
Rationale: Atomic mass is the sum of protons and neutrons in the nucleus (6 + 6 = 12).
,3. Isotopes are atoms of the same element that differ in their number of:
A. Protons
B. Neutrons
C. Electrons
D. Orbits
Answer: B
Rationale: Isotopes have the same number of protons but different numbers of neutrons,
resulting in different atomic masses.
4. Which type of chemical bond involves the complete transfer of an electron
from one atom to another?
A. Non-polar covalent bond
B. Hydrogen bond
C. Ionic bond
D. Polar covalent bond
Answer: C
Rationale: Ionic bonds form when one atom gives up an electron and another receives it,
creating oppositely charged ions that attract each other.
5. A covalent bond in which electrons are shared equally between two atoms is
called:
A. Non-polar covalent bond
B. Ionic bond
C. Polar covalent bond
D. Hydrophobic bond
Answer: A
Rationale: In non-polar covalent bonds, the electronegativity of the atoms is similar,
leading to equal sharing of electrons.
, 6. What property of water allows it to resist rapid changes in temperature?
A. High surface tension
B. Cohesive strength
C. Low density as a solid
D. High specific heat
Answer: D
Rationale: Water has a high specific heat, meaning it must absorb a significant amount of
heat energy to increase its temperature due to hydrogen bonding.
7. Which of the following is an example of adhesion?
A. Water molecules sticking to the walls of a plant vessel
B. Water molecules sticking to each other
C. Ice floating on water
D. Water dissolving sugar
Answer: A
Rationale: Adhesion is the attraction between water molecules and different substances,
such as the cellulose in plant cell walls.
8. Why does ice float on liquid water?
A. Hydrogen bonds in ice are more stable and keep molecules further apart
B. Ice is colder than water
C. Water molecules move faster in ice
D. Ice contains more air bubbles
Answer: A
Rationale: As water freezes, hydrogen bonds form a crystalline lattice that pushes
molecules further apart, making ice less dense than liquid water.
2026 |WGU
1. Which subatomic particle is primarily responsible for determining the
chemical reactivity of an atom?
A. Proton
B. Electron
C. Neutron
D. Nucleus
Answer: B
Rationale: Electrons, specifically those in the outermost shell (valence electrons), interact
with other atoms to form chemical bonds, determining reactivity.
2. An atom with 6 protons, 6 neutrons, and 6 electrons has an atomic mass of
approximately:
A. 12 amu
B. 6 amu
C. 18 amu
D. 0 amu
Answer: A
Rationale: Atomic mass is the sum of protons and neutrons in the nucleus (6 + 6 = 12).
,3. Isotopes are atoms of the same element that differ in their number of:
A. Protons
B. Neutrons
C. Electrons
D. Orbits
Answer: B
Rationale: Isotopes have the same number of protons but different numbers of neutrons,
resulting in different atomic masses.
4. Which type of chemical bond involves the complete transfer of an electron
from one atom to another?
A. Non-polar covalent bond
B. Hydrogen bond
C. Ionic bond
D. Polar covalent bond
Answer: C
Rationale: Ionic bonds form when one atom gives up an electron and another receives it,
creating oppositely charged ions that attract each other.
5. A covalent bond in which electrons are shared equally between two atoms is
called:
A. Non-polar covalent bond
B. Ionic bond
C. Polar covalent bond
D. Hydrophobic bond
Answer: A
Rationale: In non-polar covalent bonds, the electronegativity of the atoms is similar,
leading to equal sharing of electrons.
, 6. What property of water allows it to resist rapid changes in temperature?
A. High surface tension
B. Cohesive strength
C. Low density as a solid
D. High specific heat
Answer: D
Rationale: Water has a high specific heat, meaning it must absorb a significant amount of
heat energy to increase its temperature due to hydrogen bonding.
7. Which of the following is an example of adhesion?
A. Water molecules sticking to the walls of a plant vessel
B. Water molecules sticking to each other
C. Ice floating on water
D. Water dissolving sugar
Answer: A
Rationale: Adhesion is the attraction between water molecules and different substances,
such as the cellulose in plant cell walls.
8. Why does ice float on liquid water?
A. Hydrogen bonds in ice are more stable and keep molecules further apart
B. Ice is colder than water
C. Water molecules move faster in ice
D. Ice contains more air bubbles
Answer: A
Rationale: As water freezes, hydrogen bonds form a crystalline lattice that pushes
molecules further apart, making ice less dense than liquid water.
