SCH4U - Unit 2 Question and answers
100% correct 2025
Dalton (1803) - correct answer Atoms are the smallest structure (BILLIARD
BALL)
Thomson (1897) - correct answer Electrons embedded in a sphere of positive
electric charge (PLUM PUDDING)
Rutherford (1909) - correct answer Dense & positive nucleus, electrons move
randomly around the nucleus
Bohr (1913) - correct answer Electron move in spherical orbits at fixed
distances from the nucleus
Schrödinger (1926) - Quantum Model - correct answer Mathematical (wave)
equation to describe the motion of electrons in atoms (lead to electron cloud
model)
Chadwick (1932) - correct answer Confirms existence of neutrons (nucleus
contains neutrons and positively charged protons)
Rutherford's Gold Experiment
(SE SbP DR) - correct answer (Goal: Bombard thin piece of gold foil with a
stream of positively charged alpha particles and to detect their movement
through the foil)
, 1. Most of the α-particles went straight through the foil = atoms are mostly
empty space
2. Some of the positively charged α-particles were scattered back towards the
emitter = they must have been repelled by a positive part of the atom (the
nucleus is positively charged).
3. Since the alpha particles were very fast moving, they have a relatively large
momentum. The positive nucleus of the gold atom must have a large mass
(dense area) to be able to stop some of the alpha particles from moving
forward and then repel them back again.
Defraction - correct answer As white light passes through a prism, this
causes the splitting of light into 7 colours.
Highest energy colour & smallest wavelength - correct answer Violet
Lowest energy colour & longest wavelength - correct answer Red
As photon energy increases, wavelength
______________________________ (increases/decreases) - correct answer
decreases
As you go from red to violet in the rainbow, photon energy
______________________________ (increases/decreases), wavelength
______________________________ (increases/decreases) - correct answer
increases, decreases
As electron gets closer to nucleus, attraction to nucleus gets
______________________________ (stronger/weaker) - correct answer
stronger
100% correct 2025
Dalton (1803) - correct answer Atoms are the smallest structure (BILLIARD
BALL)
Thomson (1897) - correct answer Electrons embedded in a sphere of positive
electric charge (PLUM PUDDING)
Rutherford (1909) - correct answer Dense & positive nucleus, electrons move
randomly around the nucleus
Bohr (1913) - correct answer Electron move in spherical orbits at fixed
distances from the nucleus
Schrödinger (1926) - Quantum Model - correct answer Mathematical (wave)
equation to describe the motion of electrons in atoms (lead to electron cloud
model)
Chadwick (1932) - correct answer Confirms existence of neutrons (nucleus
contains neutrons and positively charged protons)
Rutherford's Gold Experiment
(SE SbP DR) - correct answer (Goal: Bombard thin piece of gold foil with a
stream of positively charged alpha particles and to detect their movement
through the foil)
, 1. Most of the α-particles went straight through the foil = atoms are mostly
empty space
2. Some of the positively charged α-particles were scattered back towards the
emitter = they must have been repelled by a positive part of the atom (the
nucleus is positively charged).
3. Since the alpha particles were very fast moving, they have a relatively large
momentum. The positive nucleus of the gold atom must have a large mass
(dense area) to be able to stop some of the alpha particles from moving
forward and then repel them back again.
Defraction - correct answer As white light passes through a prism, this
causes the splitting of light into 7 colours.
Highest energy colour & smallest wavelength - correct answer Violet
Lowest energy colour & longest wavelength - correct answer Red
As photon energy increases, wavelength
______________________________ (increases/decreases) - correct answer
decreases
As you go from red to violet in the rainbow, photon energy
______________________________ (increases/decreases), wavelength
______________________________ (increases/decreases) - correct answer
increases, decreases
As electron gets closer to nucleus, attraction to nucleus gets
______________________________ (stronger/weaker) - correct answer
stronger
