What apparatus was used in Rutherford's alpha scattering experiment?

The apparatus used in Rutherford's alpha scattering experiment was: a source of alpha particles in a lead container a thin sheet of gold foil a movable detector an evacuated chamber

What was the purpose of the lead container in Rutherford's alpha scattering experiment?

The purpose of the lead container was to produce a collimated (parallel) beam of alpha particles.

Why were gold atoms chosen as the target in Rutherford's alpha scattering experiment?

Gold atoms were chosen as the target in Rutherford's alpha scattering experiment because: alpha particles must interact with as few atoms as possible gold is very malleable and can be made into a very thin foil

Why was the apparatus placed in an evacuated chamber ?

The apparatus was placed in an evacuated chamber to prevent the alpha particles from being scattered by molecules of air.

What were the three main observations from Rutherford's alpha scattering experiment?

The three main observations from Rutherford's alpha scattering experiment were: Most alpha particles experienced no deflection Some alpha particles experienced slight deflections (angles 90°)

What does the observation that most alpha particles passed straight through the gold foil in Rutherford's alpha scattering experiment suggest about the structure of the atom?

The observation that most alpha particles passed straight through the gold foil suggests that the atom is mostly empty space .

What does the observation that some alpha particles deflect by small angles in Rutherford's alpha scattering experiment suggest about the structure of the atom?

The observation that some alpha particles deflect by small angles in Rutherford's alpha scattering experiment suggests the atom must contain a small, positive charge .

What does the observation that a tiny number of alpha particles deflect by large angles in Rutherford's alpha scattering experiment suggest about the structure of the atom?

The observation that a tiny number of alpha particles deflect by large angles suggests the majority of the mass and all of the positive charge must be concentrated in a nucleus at the centre of the atom.

What are the three subatomic particles that make up an atom?

The three subatomic particles that make up an atom are: protons (in the nucleus) neutrons (in the nucleus) electrons (around the nucleus)

True or False? The mass of a proton is exactly equal to the mass of a neutron.

False. While close, the mass of a proton (1.007276 u) is slightly less than the mass of a neutron (1.008665 u).

What is meant by the term proton number ?

The proton number of an atom is the number of protons in its nucleus. This number defines the chemical element.

What is meant by the term mass number ?

The mass number of an atom is the total number of protons and neutrons in its nucleus.

True or False? The periodic table is ordered by mass number.

False. The periodic table is ordered by proton number , not mass number.

What is the relative charge of an electron?

The relative charge of an electron is -1e , where e is the elementary charge.

True or False? Electrons make up most of the mass of an atom.

False. Most of the mass of an atom is concentrated in the nucleus . Electrons have a negligible mass compared to the mass of protons and neutrons.

What is an emission spectrum ?

An emission spectrum is a set of discrete wavelengths represented by bright lines on a black background . These lines represent the photons emitted when electrons in excited atoms transition from higher to lower energy levels.

What is an absorption spectrum ?

An absorption spectrum is a set of discrete wavelengths represented by dark lines across a continuous spectrum . These lines represent the photons absorbed when white light passes through a low-pressure gas.

True or False? Emission and absorption spectra for the same element have lines at different wavelengths.

False. Emission and absorption spectra for the same element have lines at the same wavelengths.

What do atomic spectra provide evidence for?

Atomic spectra provide evidence that electrons in atoms can only transition between discrete energy levels .

What is the main difference between emission and absorption spectra?

The main difference between emission and absorption spectra is that emission spectra appear as bright lines on a dark background, whilst absorption spectra appear as dark lines on a bright, continuous background.

True or False? Each element produces a unique pattern of spectral lines.

True. Each element produces a unique pattern of spectral lines, which can be used to identify the element.

A photon is a quantum of electromagnetic energy . They are particles with no mass and carry energy in discrete quantities.

True or False? The energy of a photon is directly proportional to its wavelength.

False. The energy of a photon is inversely proportional to its wavelength.

Define the term ionisation energy .

Ionisation energy is the minimum energy required to remove an electron from the ground state of an atom.

What happens to an atom when it absorbs a photon?

When an atom absorbs a photon, an electron moves to a higher energy level. The atom is said to be in an excited state .

True or False? The ground state is the highest possible energy state of an atom.

False. The ground state is the lowest possible energy state of an atom.

What is de-excitation ?

De-excitation is when an electron transitions from a higher energy level to a lower energy level and a photon is emitted .

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FrontRutherford's Gold Foil Experiment
What apparatus was used in Rutherford's alpha scattering experiment?
BackRutherford's Gold Foil Experiment
The apparatus used in Rutherford's alpha scattering experiment was:
a source of alpha particles in a lead container
a thin sheet of gold foil
a movable detector
an evacuated chamber
FrontRutherford's Gold Foil Experiment
Why were gold atoms chosen as the target in Rutherford's alpha scattering experiment?
BackRutherford's Gold Foil Experiment
Gold atoms were chosen as the target in Rutherford's alpha scattering experiment because:
alpha particles must interact with as few atoms as possible
gold is very malleable and can be made into a very thin foil

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What apparatus was used in Rutherford's alpha scattering experiment?
The apparatus used in Rutherford's alpha scattering experiment was:
- a source of alpha particles in a lead container
- a thin sheet of gold foil
- a movable detector
- an evacuated chamber
What was the purpose of the lead container in Rutherford's alpha scattering experiment?
The purpose of the lead container was to produce a collimated (parallel) beam of alpha particles.
Why were gold atoms chosen as the target in Rutherford's alpha scattering experiment?
Gold atoms were chosen as the target in Rutherford's alpha scattering experiment because:
- alpha particles must interact with as few atoms as possible
- gold is very malleable and can be made into a very thin foil
Why was the apparatus placed in an evacuated chamber?
The apparatus was placed in an evacuated chamber to prevent the alpha particles from being scattered by molecules of air.
What were the three main observations from Rutherford's alpha scattering experiment?
The three main observations from Rutherford's alpha scattering experiment were:
1. Most alpha particles experienced no deflection
2. Some alpha particles experienced slight deflections (angles <10°)
3. A tiny number of alpha particles experienced large deflections (angles >90°)
What does the observation that most alpha particles passed straight through the gold foil in Rutherford's alpha scattering experiment suggest about the structure of the atom?
The observation that most alpha particles passed straight through the gold foil suggests that the atom is mostly empty space.
What does the observation that some alpha particles deflect by small angles in Rutherford's alpha scattering experiment suggest about the structure of the atom?
The observation that some alpha particles deflect by small angles in Rutherford's alpha scattering experiment suggests the atom must contain a small, positive charge.
What does the observation that a tiny number of alpha particles deflect by large angles in Rutherford's alpha scattering experiment suggest about the structure of the atom?
The observation that a tiny number of alpha particles deflect by large angles suggests the majority of the mass and all of the positive charge must be concentrated in a nucleus at the centre of the atom.
What are the three subatomic particles that make up an atom?
The three subatomic particles that make up an atom are:
- protons (in the nucleus)
- neutrons (in the nucleus)
- electrons (around the nucleus)
True or False?
The mass of a proton is exactly equal to the mass of a neutron.
False.
While close, the mass of a proton (1.007276 u) is slightly less than the mass of a neutron (1.008665 u).
What is meant by the term proton number?
The proton number of an atom is the number of protons in its nucleus. This number defines the chemical element.
What is meant by the term mass number?
The mass number of an atom is the total number of protons and neutrons in its nucleus.
True or False?
The periodic table is ordered by mass number.
False.
The periodic table is ordered by proton number, not mass number.
What is the relative charge of an electron?
The relative charge of an electron is -1e, where e is the elementary charge.
True or False?
Electrons make up most of the mass of an atom.
False.
Most of the mass of an atom is concentrated in the nucleus. Electrons have a negligible mass compared to the mass of protons and neutrons.
How can the notation below be used to determine the number of protons, neutrons and electrons in atom X?
In nuclear notation:
- X represents the chemical symbol
- A represents the mass number (number of protons and neutrons)
- Z represents the atomic number (number of protons)
Therefore, Z = number of protons = number of electrons, and A - Z = number of neutrons.
What is the mass number and proton number of carbon?
The mass number (top number) of carbon is 12.
The proton number (bottom number) of carbon is 6.
How many protons, neutrons and electrons are in an atom of beryllium?
The mass number (top number) of beryllium is 9.
The proton number (bottom number) of beryllium is 4.
Therefore, an atom of beryllium contains 4 protons, 5 neutrons and 4 electrons.
What is an emission spectrum?
An emission spectrum is a set of discrete wavelengths represented by bright lines on a black background.
These lines represent the photons emitted when electrons in excited atoms transition from higher to lower energy levels.
What is an absorption spectrum?
An absorption spectrum is a set of discrete wavelengths represented by dark lines across a continuous spectrum.
These lines represent the photons absorbed when white light passes through a low-pressure gas.
True or False?
Emission and absorption spectra for the same element have lines at different wavelengths.
False.
Emission and absorption spectra for the same element have lines at the same wavelengths.
What do atomic spectra provide evidence for?
Atomic spectra provide evidence that electrons in atoms can only transition between discrete energy levels.
What is the main difference between emission and absorption spectra?
The main difference between emission and absorption spectra is that emission spectra appear as bright lines on a dark background, whilst absorption spectra appear as dark lines on a bright, continuous background.
True or False?
Each element produces a unique pattern of spectral lines.
True.
Each element produces a unique pattern of spectral lines, which can be used to identify the element.
Define a photon.
A photon is a quantum of electromagnetic energy.
They are particles with no mass and carry energy in discrete quantities.
What is the equation for photon energy?
The equation for photon energy is: $E = h f = \frac{h c}{λ}$
Where:
- $h$ = Planck's constant (6.63 × 10^-34 J s)
- $c$ = speed of light (3.0 × 10⁸ m s^-1)
- $f$ = frequency of photon (Hz)
- $λ$ = wavelength of photon (m)
True or False?
The energy of a photon is directly proportional to its wavelength.
False.
The energy of a photon is inversely proportional to its wavelength.
Define the term ionisation energy.
Ionisation energy is the minimum energy required to remove an electron from the ground state of an atom.
What happens to an atom when it absorbs a photon?
When an atom absorbs a photon, an electron moves to a higher energy level.
The atom is said to be in an excited state.
True or False?
The ground state is the highest possible energy state of an atom.
False.
The ground state is the lowest possible energy state of an atom.
What is de-excitation?
De-excitation is when an electron transitions from a higher energy level to a lower energy level and a photon is emitted.
What is the equation for the energy difference between two atomic energy levels?
The equation for the difference between the two energy levels is: $∆ E = E_{2} - E_{1} = h f$
Where:
- $E_{1}$ = the energy of the lower level (J)
- $E_{2}$ = the energy of the higher level (J)
- $h$ = Planck's constant (6.63 × 10^-34 J s)
- $f$ = the frequency of the emitted or absorbed photon (Hz)