Where in an atom are protons and neutrons found, and where are electrons found?

Protons and neutrons are found in the nucleus Electrons orbit the nucleus

A stable atom is electrically .......... because it contains equal numbers of protons and electrons.

A stable atom is electrically neutral because it contains equal numbers of protons and electrons.

What are the specific charges of the electron and the proton?

Electron: 1.76 × 10 11 C kg -1 Proton: 9.58 × 10 7 C kg -1

True or False? The nucleus of an atom includes the electrons as well as the protons and neutrons.

False. The nucleus consists only of protons and neutrons . The electrons orbit the nucleus and are not part of it.

When calculating the specific charge of an ion, how are the total charge and total mass found?

Charge = number of electrons added or removed × 1.60 × 10 -19 C Mass = total number of nucleons × 1.67 × 10 -27 kg

Define nucleon number .

The nucleon number (A) is the total number of protons and neutrons in a nucleus.

Define proton number .

The proton number (Z) is the total number of protons in a nucleus.

Isotopes are nuclei that have the same number of protons but different numbers of neutrons .

What other names are used for nucleon number and proton number, for example in Chemistry?

Nucleon number is also called the mass number Proton number is also called the atomic number

Isotopes of an element have a fixed proton number but a .......... nucleon number.

Isotopes of an element have a fixed proton number but a different nucleon number.

What is isotopic data?

The relative amounts of different isotopes of an element present within a substance.

Which two isotopes of carbon are compared in carbon dating, and which one is unstable?

Carbon-12 (stable) and carbon-14 (unstable) The ratio of carbon-14 to carbon-12 in a sample is compared to the ratio in living tissue to estimate its age

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

False. The periodic table is ordered by proton number (atomic number), not nucleon number.

Define strong nuclear force .

The strong nuclear force is the short-range attractive force that acts between nucleons (via the quarks within them), holding the nucleus together and overcoming electrostatic repulsion between protons.

Why can gravitational and electrostatic forces alone not hold a nucleus together?

Electrostatic repulsion between protons would push the nucleus apart Gravitational attraction between nucleons is far too weak to counteract this

Over what range of separation is the strong nuclear force attractive, and at what separation is the attraction maximum?

Attractive up to a separation of 3.0 fm Maximum attraction occurs at around 1.0 fm (a typical nucleon separation)

Below a separation of 0.5 fm, the strong nuclear force becomes .......... .

Below a separation of 0.5 fm, the strong nuclear force becomes repulsive .

How does the strength of the strong nuclear force compare between proton-proton, neutron-neutron and proton-neutron pairs, at separations of 0.5 to 3.0 fm?

It is roughly the same for all combinations, since the strong nuclear force does not depend on charge.

True or False? Beyond a separation of 3.0 fm, the strong nuclear force is best described as negligible .

False. Beyond 3.0 fm the strong nuclear force has no effect (it is zero), rather than merely negligible.

What is an alpha particle equivalent to, and what is its composition?

An alpha particle consists of two protons and two neutrons — equivalent to a helium nucleus .

How do the proton number and nucleon number of a nucleus change during alpha decay?

Proton number decreases by 2 Nucleon number decreases by 4

What happens to a neutron during beta-minus decay, and what two particles are emitted?

A neutron turns into a proton , emitting an electron and an anti-electron neutrino .

What happens to a proton during beta-plus decay, and what two particles are emitted?

A proton turns into a neutron , emitting a positron and an electron neutrino .

In beta-minus decay, the nucleon number stays the .......... while the proton number increases by one.

In beta-minus decay, the nucleon number stays the same while the proton number increases by one.

Which type of neutrino is produced during β - decay, and which during β + decay?

β - decay produces an electron anti-neutrino β + decay produces an electron neutrino

Define electron neutrino .

An electron neutrino is a subatomic particle with no charge and negligible mass , emitted from the nucleus during beta decay.

True or False? During alpha decay, the number of neutrons in the nucleus decreases by four.

False. The nucleon number decreases by four, but since an alpha particle contains two protons and two neutrons, the neutron number only decreases by two .

How does the energy spectrum of emitted alpha particles differ from that of emitted beta particles?

Alpha particles have discrete (fixed) energies Beta particles have a continuous range of energies, because the energy released is shared between the beta particle and the neutrino (or anti-neutrino)

How does an antiparticle compare to its corresponding matter particle in charge, mass and rest mass-energy?

Opposite charge Same mass Same rest mass-energy

Define rest mass-energy .

The rest mass-energy of a particle is the energy equivalent to the mass of the particle when it is at rest .

How is an antiparticle's symbol usually named and written, and what is the exception?

Antiparticles are named with the prefix 'anti-' and a line above the matter particle's symbol The exception is the electron , whose antiparticle is called the positron

A photon is a massless 'packet' or 'quantum' of electromagnetic energy.

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

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

Define annihilation .

Annihilation is the destruction of a particle-antiparticle pair when they collide and convert their mass into two gamma-ray photons .

Define pair production .

Pair production is the creation of a particle-antiparticle pair when a high-energy photon spontaneously converts its energy into mass .

True or False? In annihilation, the two gamma-ray photons produced travel off in the same direction.

False. To conserve momentum , the two photons move apart in opposite directions.

A LevelPhysicsAQAFlashcardsParticles & RadiationAtomic Structure & Decay Equations

Atomic Structure & Decay Equations (AQA A Level Physics): Flashcards

Exam code: 7408

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FrontAtomic Structure
Define specific charge.
FrontAtomic Structure
What three types of particle make up an atom?
BackAtomic Structure
Protons
Neutrons
Electrons
FrontAtomic Structure
Where in an atom are protons and neutrons found, and where are electrons found?
BackAtomic Structure
Protons and neutrons are found in the nucleus
Electrons orbit the nucleus

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Cards in this collection (42)

Define specific charge.
Specific charge is the ratio of the total charge of a particle to its mass:
$specific charge = \frac{Q}{m}$
It is measured in coulombs per kilogram (C kg^-1).
What three types of particle make up an atom?
- Protons
- Neutrons
- Electrons
Where in an atom are protons and neutrons found, and where are electrons found?
- Protons and neutrons are found in the nucleus
- Electrons orbit the nucleus
A stable atom is electrically .......... because it contains equal numbers of protons and electrons.
A stable atom is electrically neutral because it contains equal numbers of protons and electrons.
What are the specific charges of the electron and the proton?
- Electron: 1.76 × 10¹¹ C kg^-1
- Proton: 9.58 × 10⁷ C kg^-1
True or False?
The nucleus of an atom includes the electrons as well as the protons and neutrons.
False.
The nucleus consists only of protons and neutrons. The electrons orbit the nucleus and are not part of it.
When calculating the specific charge of an ion, how are the total charge and total mass found?
- Charge = number of electrons added or removed × 1.60 × 10^-19 C
- Mass = total number of nucleons × 1.67 × 10^-27 kg
Define nucleon number.
The nucleon number (A) is the total number of protons and neutrons in a nucleus.
Define proton number.
The proton number (Z) is the total number of protons in a nucleus.
Define isotopes.
Isotopes are nuclei that have the same number of protons but different numbers of neutrons.
What other names are used for nucleon number and proton number, for example in Chemistry?
- Nucleon number is also called the mass number
- Proton number is also called the atomic number
Isotopes of an element have a fixed proton number but a .......... nucleon number.
Isotopes of an element have a fixed proton number but a different nucleon number.
What is isotopic data?
The relative amounts of different isotopes of an element present within a substance.
Which two isotopes of carbon are compared in carbon dating, and which one is unstable?
- Carbon-12 (stable) and carbon-14 (unstable)
- The ratio of carbon-14 to carbon-12 in a sample is compared to the ratio in living tissue to estimate its age
True or False?
The periodic table is ordered by nucleon number.
False.
The periodic table is ordered by proton number (atomic number), not nucleon number.
Define strong nuclear force.
The strong nuclear force is the short-range attractive force that acts between nucleons (via the quarks within them), holding the nucleus together and overcoming electrostatic repulsion between protons.
Why can gravitational and electrostatic forces alone not hold a nucleus together?
- Electrostatic repulsion between protons would push the nucleus apart
- Gravitational attraction between nucleons is far too weak to counteract this
Over what range of separation is the strong nuclear force attractive, and at what separation is the attraction maximum?
- Attractive up to a separation of 3.0 fm
- Maximum attraction occurs at around 1.0 fm (a typical nucleon separation)
Below a separation of 0.5 fm, the strong nuclear force becomes ...........
Below a separation of 0.5 fm, the strong nuclear force becomes repulsive.
At what nucleon separation is the resultant strong nuclear force zero (the equilibrium position)?
Around 0.5 fm.
How does the strength of the strong nuclear force compare between proton-proton, neutron-neutron and proton-neutron pairs, at separations of 0.5 to 3.0 fm?
It is roughly the same for all combinations, since the strong nuclear force does not depend on charge.
True or False?
Beyond a separation of 3.0 fm, the strong nuclear force is best described as negligible.
False.
Beyond 3.0 fm the strong nuclear force has no effect (it is zero), rather than merely negligible.
At what nucleon separation are the strong attractive force and electrostatic repulsive force equal in magnitude, for two protons?
Around 0.7 fm.
What is an alpha particle equivalent to, and what is its composition?
An alpha particle consists of two protons and two neutrons — equivalent to a helium nucleus.
How do the proton number and nucleon number of a nucleus change during alpha decay?
- Proton number decreases by 2
- Nucleon number decreases by 4
What happens to a neutron during beta-minus decay, and what two particles are emitted?
A neutron turns into a proton, emitting an electron and an anti-electron neutrino.
What happens to a proton during beta-plus decay, and what two particles are emitted?
A proton turns into a neutron, emitting a positron and an electron neutrino.
In beta-minus decay, the nucleon number stays the .......... while the proton number increases by one.
In beta-minus decay, the nucleon number stays the same while the proton number increases by one.
Which type of neutrino is produced during β^- decay, and which during β⁺ decay?
- β^- decay produces an electron anti-neutrino
- β⁺ decay produces an electron neutrino
Define electron neutrino.
An electron neutrino is a subatomic particle with no charge and negligible mass, emitted from the nucleus during beta decay.
True or False?
During alpha decay, the number of neutrons in the nucleus decreases by four.
False.
The nucleon number decreases by four, but since an alpha particle contains two protons and two neutrons, the neutron number only decreases by two.
How does the energy spectrum of emitted alpha particles differ from that of emitted beta particles?
- Alpha particles have discrete (fixed) energies
- Beta particles have a continuous range of energies, because the energy released is shared between the beta particle and the neutrino (or anti-neutrino)
How does an antiparticle compare to its corresponding matter particle in charge, mass and rest mass-energy?
- Opposite charge
- Same mass
- Same rest mass-energy
Define rest mass-energy.
The rest mass-energy of a particle is the energy equivalent to the mass of the particle when it is at rest.
How is an antiparticle's symbol usually named and written, and what is the exception?
- Antiparticles are named with the prefix 'anti-' and a line above the matter particle's symbol
- The exception is the electron, whose antiparticle is called the positron
Define a photon.
A photon is a massless 'packet' or 'quantum' of electromagnetic energy.
The energy of a photon is .......... proportional to its wavelength.
The energy of a photon is inversely proportional to its wavelength.
Write two equations for the energy of a photon.
$E = h f$
$E = \frac{h c}{λ}$
Define annihilation.
Annihilation is the destruction of a particle-antiparticle pair when they collide and convert their mass into two gamma-ray photons.
Define pair production.
Pair production is the creation of a particle-antiparticle pair when a high-energy photon spontaneously converts its energy into mass.
What is the minimum photon energy condition for (a) annihilation producing one photon, and (b) pair production, in terms of the rest mass energy E of one particle?
- Annihilation (one photon): $E_{m i n} = h f_{m i n} = E$
- Pair production: $E_{m i n} = h f_{m i n} = 2 E$
True or False?
In annihilation, the two gamma-ray photons produced travel off in the same direction.
False.
To conserve momentum, the two photons move apart in opposite directions.

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