SCH4U Unit 2 Review exam fully solved &
updated 2025-2026(latest version verified for
accuracy)
something that uses familiar ideas to explain unfamiliar facts observed
in nature is known as... - answer--a model. it can be changed as new
information is collected
T or F: the atomic model started out in 400 BC, having the appearance
of a billiard ball - answer--true
who was the greek philosopher that began the search for a description
of matter? - answer--Democritus; over 2400 years ago!
democritus named the smallest piece of matter ______, which meant
___ __ __ ___ - answer--atomos, not to be cut
what is the name of the current theory we use for atoms? - answer--the
modern wave model
which english chemist from the 1800s deduced that...
1. all elements are composed of atoms which are indivisible and
indestructable
,2. atoms of the same element are exactly alike
3. compounds are formed by the joining of two or more atoms -
answer--dalton
who came up with the plum pudding model ( in 1897), and what did it
imply about atoms? (3 points) - answer--J.J Thompson; implied that an
atom is made of even smaller particles, and WAS divisible
J.J Thompson discovered the electron through what? - answer--by
passing an electric current through a gas (which gave off rays of
negatively charged particles)
rutherford's experiment involved shooting _____ particles at a thin
sheet of ____ foil. - answer--alpha, gold
in Rutherford's gold foil experiment, some of the alpha partices
bounced back as opposed to going through the gold sheet.
this meant that... (2 points) - answer--1. atoms are mostly made of open
space
2. the center of the atom was positively charged
, Niels Bohr created the theory that.... - answer--electrons move in
definite orbits around the nucleus that were considered "energy levels"
the locations of electrons depends on how much ______ the electron
has. - answer--energy
what experiments/study did Max Planck start the quantum revolution
from? - answer--the light emitted by hot objects
why does an object turn from red to white as it gets hotter? (blackbody
radiation) - answer--as the objects gets hotter, the light emitted by the
object must be accompanied by light of higher wavelength (e.g blue)
How was the ultraviolet catastrophe solved? - answer--by assuming that
energy was NOT continuously divisible, but rather that it comes in
discrete "packets" or quanta!
T or F: energy is continuous - answer--false: proven mathematically by
Max Planck, the energy of the oscillating atoms in heated solids with
multiples of a small quantity of energy
what is known as a small discrete, indivisible quantity? what is this for
light? - answer--quantum (plural; quanta), photon
updated 2025-2026(latest version verified for
accuracy)
something that uses familiar ideas to explain unfamiliar facts observed
in nature is known as... - answer--a model. it can be changed as new
information is collected
T or F: the atomic model started out in 400 BC, having the appearance
of a billiard ball - answer--true
who was the greek philosopher that began the search for a description
of matter? - answer--Democritus; over 2400 years ago!
democritus named the smallest piece of matter ______, which meant
___ __ __ ___ - answer--atomos, not to be cut
what is the name of the current theory we use for atoms? - answer--the
modern wave model
which english chemist from the 1800s deduced that...
1. all elements are composed of atoms which are indivisible and
indestructable
,2. atoms of the same element are exactly alike
3. compounds are formed by the joining of two or more atoms -
answer--dalton
who came up with the plum pudding model ( in 1897), and what did it
imply about atoms? (3 points) - answer--J.J Thompson; implied that an
atom is made of even smaller particles, and WAS divisible
J.J Thompson discovered the electron through what? - answer--by
passing an electric current through a gas (which gave off rays of
negatively charged particles)
rutherford's experiment involved shooting _____ particles at a thin
sheet of ____ foil. - answer--alpha, gold
in Rutherford's gold foil experiment, some of the alpha partices
bounced back as opposed to going through the gold sheet.
this meant that... (2 points) - answer--1. atoms are mostly made of open
space
2. the center of the atom was positively charged
, Niels Bohr created the theory that.... - answer--electrons move in
definite orbits around the nucleus that were considered "energy levels"
the locations of electrons depends on how much ______ the electron
has. - answer--energy
what experiments/study did Max Planck start the quantum revolution
from? - answer--the light emitted by hot objects
why does an object turn from red to white as it gets hotter? (blackbody
radiation) - answer--as the objects gets hotter, the light emitted by the
object must be accompanied by light of higher wavelength (e.g blue)
How was the ultraviolet catastrophe solved? - answer--by assuming that
energy was NOT continuously divisible, but rather that it comes in
discrete "packets" or quanta!
T or F: energy is continuous - answer--false: proven mathematically by
Max Planck, the energy of the oscillating atoms in heated solids with
multiples of a small quantity of energy
what is known as a small discrete, indivisible quantity? what is this for
light? - answer--quantum (plural; quanta), photon
