INTRODUCTION TO CHEMICAL PRINCIPLES
2026 CERTIFICATION EVALUATION TEST PAPER
QUESTIONS SOLUTIONS GRADED A PLUS
◉ How is an atom defined in terms of its properties?
Answer: An atom is the smallest component of a substance that
cannot be subdivided into smaller substances without losing its
unique properties.
◉ What is formed when atoms combine with one another?
Answer: Atoms combine to form molecules.
◉ What are living cells primarily made of?
Answer: Living cells are made up of molecules, some of which are
very complex.
◉ How is the science of the interaction between atoms and
molecules defined?
Answer: This field of science is called chemistry.
◉ What is defined as the smallest unit of matter that enters into
chemical reactions?
,Answer: An atom.
◉ What are the three primary subatomic particles that make up an
atom?
Answer: Protons, neutrons, and electrons.
◉ Where are electrons located within an atom?
Answer: They move around the nucleus in regions called electron
shells.
◉ What is the electrical charge of an electron?
Answer: Negatively charged.
◉ What particles are found within the nucleus of an atom?
Answer: Protons and neutrons.
◉ What are the electrical charges of protons and neutrons?
Answer: Protons are positively charged, and neutrons are uncharged
(neutral).
◉ Why does an atom have a net neutral electrical charge?
Answer: Because the number of protons equals the number of
electrons, balancing the positive and negative charges.
,◉ Do atomic nuclei typically participate in chemical reactions?
Answer: No, the nuclei of most atoms are stable and do not
participate in chemical reactions.
◉ 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.
2026 CERTIFICATION EVALUATION TEST PAPER
QUESTIONS SOLUTIONS GRADED A PLUS
◉ How is an atom defined in terms of its properties?
Answer: An atom is the smallest component of a substance that
cannot be subdivided into smaller substances without losing its
unique properties.
◉ What is formed when atoms combine with one another?
Answer: Atoms combine to form molecules.
◉ What are living cells primarily made of?
Answer: Living cells are made up of molecules, some of which are
very complex.
◉ How is the science of the interaction between atoms and
molecules defined?
Answer: This field of science is called chemistry.
◉ What is defined as the smallest unit of matter that enters into
chemical reactions?
,Answer: An atom.
◉ What are the three primary subatomic particles that make up an
atom?
Answer: Protons, neutrons, and electrons.
◉ Where are electrons located within an atom?
Answer: They move around the nucleus in regions called electron
shells.
◉ What is the electrical charge of an electron?
Answer: Negatively charged.
◉ What particles are found within the nucleus of an atom?
Answer: Protons and neutrons.
◉ What are the electrical charges of protons and neutrons?
Answer: Protons are positively charged, and neutrons are uncharged
(neutral).
◉ Why does an atom have a net neutral electrical charge?
Answer: Because the number of protons equals the number of
electrons, balancing the positive and negative charges.
,◉ Do atomic nuclei typically participate in chemical reactions?
Answer: No, the nuclei of most atoms are stable and do not
participate in chemical reactions.
◉ 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.
