INTRODUCTION TO CHEMICAL PRINCIPLES
2026 COMPREHENSIVE ASSESSMENT SCRIPT
SOLVED QUESTIONS ANSWERS UPDATED
REVIEW SET
◉ How is the atomic number of an element defined?
Answer: It is the number of protons in the nucleus.
◉ How does the mass of a proton or neutron compare to the mass of
an electron?
Answer: Protons and neutrons are approximately 1840 times
heavier than an electron.
◉ What determines the approximate atomic mass of an atom?
Answer: The total number of protons and neutrons in the atom.
◉ What determines whether atoms are classified as the same
chemical element?
Answer: Atoms with the same number of protons behave the same
way chemically and are classified as the same element.
◉ What is the origin of most chemical element symbols?
,Answer: They are usually derived from the English or Latin name for
the element.
◉ Why is the symbol for sodium 'Na'?
Answer: It is derived from its Latin name, 'natrium', to distinguish it
from nitrogen (N) and sulfur (S).
◉ Approximately how many elements are commonly found in living
things?
Answer: About 26 elements.
◉ What is the definition of an isotope?
Answer: Isotopes are atoms of the same element that have different
numbers of neutrons in their nuclei.
◉ Do isotopes of the same element have the same number of
protons?
Answer: Yes, all isotopes of an element have the same number of
protons.
◉ Why do isotopes of the same element have different atomic
masses?
Answer: Because they have different numbers of neutrons in their
nuclei.
,◉ In the isotope notation 16 8O, what does the subscript 8
represent?
Answer: The atomic number (number of protons).
◉ In the isotope notation 16 8O, what does the superscript 16
represent?
Answer: The atomic mass.
◉ How many naturally occurring elements are there?
Answer: 92.
◉ If an oxygen atom has 8 protons and 9 neutrons, what is its atomic
mass?
Answer: 17.
◉ Do all isotopes of a single element behave the same way
chemically?
Answer: Yes, because they have the same number of protons.
◉ What are some practical applications of isotopes?
Answer: Biological research, medical diagnosis, treatment of some
disorders, and sterilization.
, ◉ What is the atomic number of all oxygen isotopes?
Answer: 8.
◉ How are atomic numbers and atomic masses positioned relative
to an element's symbol?
Answer: The atomic number is written as a subscript to the left, and
the atomic mass is written as a superscript above the atomic
number.
◉ Hydrogen
Answer: Symbol: H, Atomic Number: 1, Approximate Atomic Mass: 1
◉ Carbon
Answer: Symbol: C, Atomic Number: 6, Approximate Atomic Mass:
12
◉ Nitrogen
Answer: Symbol: N, Atomic Number: 7, Approximate Atomic Mass:
14
◉ Oxygen
2026 COMPREHENSIVE ASSESSMENT SCRIPT
SOLVED QUESTIONS ANSWERS UPDATED
REVIEW SET
◉ How is the atomic number of an element defined?
Answer: It is the number of protons in the nucleus.
◉ How does the mass of a proton or neutron compare to the mass of
an electron?
Answer: Protons and neutrons are approximately 1840 times
heavier than an electron.
◉ What determines the approximate atomic mass of an atom?
Answer: The total number of protons and neutrons in the atom.
◉ What determines whether atoms are classified as the same
chemical element?
Answer: Atoms with the same number of protons behave the same
way chemically and are classified as the same element.
◉ What is the origin of most chemical element symbols?
,Answer: They are usually derived from the English or Latin name for
the element.
◉ Why is the symbol for sodium 'Na'?
Answer: It is derived from its Latin name, 'natrium', to distinguish it
from nitrogen (N) and sulfur (S).
◉ Approximately how many elements are commonly found in living
things?
Answer: About 26 elements.
◉ What is the definition of an isotope?
Answer: Isotopes are atoms of the same element that have different
numbers of neutrons in their nuclei.
◉ Do isotopes of the same element have the same number of
protons?
Answer: Yes, all isotopes of an element have the same number of
protons.
◉ Why do isotopes of the same element have different atomic
masses?
Answer: Because they have different numbers of neutrons in their
nuclei.
,◉ In the isotope notation 16 8O, what does the subscript 8
represent?
Answer: The atomic number (number of protons).
◉ In the isotope notation 16 8O, what does the superscript 16
represent?
Answer: The atomic mass.
◉ How many naturally occurring elements are there?
Answer: 92.
◉ If an oxygen atom has 8 protons and 9 neutrons, what is its atomic
mass?
Answer: 17.
◉ Do all isotopes of a single element behave the same way
chemically?
Answer: Yes, because they have the same number of protons.
◉ What are some practical applications of isotopes?
Answer: Biological research, medical diagnosis, treatment of some
disorders, and sterilization.
, ◉ What is the atomic number of all oxygen isotopes?
Answer: 8.
◉ How are atomic numbers and atomic masses positioned relative
to an element's symbol?
Answer: The atomic number is written as a subscript to the left, and
the atomic mass is written as a superscript above the atomic
number.
◉ Hydrogen
Answer: Symbol: H, Atomic Number: 1, Approximate Atomic Mass: 1
◉ Carbon
Answer: Symbol: C, Atomic Number: 6, Approximate Atomic Mass:
12
◉ Nitrogen
Answer: Symbol: N, Atomic Number: 7, Approximate Atomic Mass:
14
◉ Oxygen
