SCH4U Unit 1 Exam Questions with Correct Answers Latest Update 2025-2026
Democritus and Leucippus - Answers Greek philosophers who speculated that matter is
composed of elementary particles called "atoms"
Who discovered negatively charged electrons? - Answers J.J. Thompson
What did J.J. Thompson use to show that there are positively and negatively charged
components to matter? - Answers Discharge tubes
In which time period did J.J. Thompson make his discoveries? - Answers Late 1800s
What did J.J. Thompson theorize about the distribution of electrons? - Answers Electrons were
distributed randomly in a positively charged matrix
Earnest Rutherford (1909) - Answers Who discovered that positive charges are concentrated in
the atom and that the nucleus consists of positive charges concentrated in the centre?
What experiment did Earnest Rutherford conduct? - Answers Rutherford's Gold Foil Experiment
He shot positively charged alphas particles at a thin piece of gold foil and observed some
particles deflect off of the foil.
Neil's Bohr (1911) - Answers Discoverd that electrons orbit a central nuceus using Rutherford's
gold foil experiment to estimate the most likely positions of electrons in an atom.
Who discovered that electrons orbit? - Answers Werner Heisenberg
What principle states that it is impossible to know the position and momentum of an electron
simultaneously? - Answers Heisenberg Uncertainty Principle
What did Werner Heisenberg theorize about electrons? - Answers Electrons are not particles nor
waves.
Neils Bohr (1911) - Answers Who stated that electrons are capable of absorbing energy and
releasing energy as light?
State every energy sublevel. - Answers sharp (s)
principle (p)
diffuse (d)
fundamental (f)
How many electrons can a s-shell hold? - Answers 2 electrons
How many electrons can a p-shell hold? - Answers 6 electrons
, How many electrons can a d-shell hold? - Answers 10 electrons
How many electrons can an f-shell hold? - Answers 14 electrons
What is the Pauli Exclusion Principle? - Answers No two electrons within a particular atom can
share the same "location"
What is Hund's Rule? - Answers As electrons are added to an atom, electrons enter into an
empty orbital first before filling previous orbitals.
What is in the electromagnetic spectrum? - Answers Light in the form of energy exists as a
wave.
What does every wave have? - Answers A wavelength and frequency.
What is the photoelectric effect? - Answers States that energy is transmitted from light to
electrons in the atoms of a metal and allows for them to move and produce current.
What is light made up of, according to Einstein? - Answers Photons
What is De Broglie's Proposition? (1924) - Answers Matter can behave as a wave and a particle.
What is Schrodinger's Theory? - Answers Schrodinger described regions of space around the
nucleus of an atom as atomic orbitals. Electrons can exist only in "acceptable" areas.
What are valence electrons? - Answers Electrons that exist in orbtials
An atom with a full shell of valence electrons are... - Answers Stable and unreactive
Electrons are better described as (blank) rather than (blank). - Answers waves, particles
What is a crystal? - Answers A solid is a substance where the molecules that make up the solid
are in a relatively consistent pattern.
What are covalent networks? - Answers Consist of molecules/atoms that share electrons with
each other.
What are ionic crystals? - Answers A bond between two crystals where one atom gives an
electron to the other.
What are metallic crystals? - Answers Invovles metals that allow for their electrons to "roam
free".
Bonds with a difference in electronegativity less than (blank) are covalent. - Answers 1.67
What are dipoles? - Answers A substance that has a positive side and a negative side.
Name all the intermolecular forces from strongest to weakest. - Answers 1. Ion-ion Interaction
Democritus and Leucippus - Answers Greek philosophers who speculated that matter is
composed of elementary particles called "atoms"
Who discovered negatively charged electrons? - Answers J.J. Thompson
What did J.J. Thompson use to show that there are positively and negatively charged
components to matter? - Answers Discharge tubes
In which time period did J.J. Thompson make his discoveries? - Answers Late 1800s
What did J.J. Thompson theorize about the distribution of electrons? - Answers Electrons were
distributed randomly in a positively charged matrix
Earnest Rutherford (1909) - Answers Who discovered that positive charges are concentrated in
the atom and that the nucleus consists of positive charges concentrated in the centre?
What experiment did Earnest Rutherford conduct? - Answers Rutherford's Gold Foil Experiment
He shot positively charged alphas particles at a thin piece of gold foil and observed some
particles deflect off of the foil.
Neil's Bohr (1911) - Answers Discoverd that electrons orbit a central nuceus using Rutherford's
gold foil experiment to estimate the most likely positions of electrons in an atom.
Who discovered that electrons orbit? - Answers Werner Heisenberg
What principle states that it is impossible to know the position and momentum of an electron
simultaneously? - Answers Heisenberg Uncertainty Principle
What did Werner Heisenberg theorize about electrons? - Answers Electrons are not particles nor
waves.
Neils Bohr (1911) - Answers Who stated that electrons are capable of absorbing energy and
releasing energy as light?
State every energy sublevel. - Answers sharp (s)
principle (p)
diffuse (d)
fundamental (f)
How many electrons can a s-shell hold? - Answers 2 electrons
How many electrons can a p-shell hold? - Answers 6 electrons
, How many electrons can a d-shell hold? - Answers 10 electrons
How many electrons can an f-shell hold? - Answers 14 electrons
What is the Pauli Exclusion Principle? - Answers No two electrons within a particular atom can
share the same "location"
What is Hund's Rule? - Answers As electrons are added to an atom, electrons enter into an
empty orbital first before filling previous orbitals.
What is in the electromagnetic spectrum? - Answers Light in the form of energy exists as a
wave.
What does every wave have? - Answers A wavelength and frequency.
What is the photoelectric effect? - Answers States that energy is transmitted from light to
electrons in the atoms of a metal and allows for them to move and produce current.
What is light made up of, according to Einstein? - Answers Photons
What is De Broglie's Proposition? (1924) - Answers Matter can behave as a wave and a particle.
What is Schrodinger's Theory? - Answers Schrodinger described regions of space around the
nucleus of an atom as atomic orbitals. Electrons can exist only in "acceptable" areas.
What are valence electrons? - Answers Electrons that exist in orbtials
An atom with a full shell of valence electrons are... - Answers Stable and unreactive
Electrons are better described as (blank) rather than (blank). - Answers waves, particles
What is a crystal? - Answers A solid is a substance where the molecules that make up the solid
are in a relatively consistent pattern.
What are covalent networks? - Answers Consist of molecules/atoms that share electrons with
each other.
What are ionic crystals? - Answers A bond between two crystals where one atom gives an
electron to the other.
What are metallic crystals? - Answers Invovles metals that allow for their electrons to "roam
free".
Bonds with a difference in electronegativity less than (blank) are covalent. - Answers 1.67
What are dipoles? - Answers A substance that has a positive side and a negative side.
Name all the intermolecular forces from strongest to weakest. - Answers 1. Ion-ion Interaction
