Atom Structure and Decay Equations Flashcards

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1
Q

What is the relative and normal charge and mass of a proton?

A
  • Charge: 1.6x10^-19
  • Mass: 1.673x10^-27
  • Relative Charge: +1
  • Relative Mass: +1
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2
Q

What is the relative and normal charge and mass of a neutron?

A
  • Charge: 0
  • Mass: 1.675x10^-27
  • Relative Charge: 0
  • Relative Mass: +1
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2
Q

What is the relative and normal charge and mass of an electron?

A
  • Charge: -1.6x10^-19
  • Mass: 9.11x10^-31
  • Relative Charge: -1
  • Relative Mass: 1/2000 (negligible)
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3
Q

How do you calculate Specific Charge of an ion and what are its units?

A
  • Equation: Charge/Mass = Total number of electrons added / removed × (1.60 × 10^-19 C) / Total number of nucleons × (1.67 × 10^-27 kg)
  • Units: Coulombs per kg (C kg^-1)
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3
Q

How do you calculate Specific Charge of a nucleus and what are its units?

A
  • Equation: Charge/Mass = Total charge of protons × (1.60 × 10^-19 C) / Total number of nucleons × (1.67 × 10^-27 kg)
  • Units: Coulombs per kg (C kg^-1)
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4
Q

What is an isotope?

A
  • An atom (of the same element) that has an equal number of protons but a different number of neutrons
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5
Q

Why are isotopes unstable atoms?

A
  • Since isotopes have an imbalance of neutrons and protons, they are unstable (charge isn’t only thing that causes stability/instability in atom, mass does too)
  • This means they constantly decay and emit radiation to achieve a more stable form, which can happen from anywhere between a few nanoseconds to 100,000 years
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6
Q

What is isotopic data?

A
  • The relative amounts of different isotopes of an element found within a substance
  • Isotopic data is often used for determining the age of archaeological findings and is used in radioactive dating
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7
Q

What is an example of use of isotopic data?

A
  • Carbon–14 is present in all living beings and undergoes radioactive decay
  • When a plant or animal dies, the natural decay of this isotope means the concentration of the carbon–14 in its tissue gradually reduces
  • Carbon–14 has a long half-life of around 6000 years, the half-life can be used to determine the age of the plant or animal when it died
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8
Q

What is a strong nuclear force?

A
  • Electrostatic repulsion forces protons in nucleus apart
  • Gravitational forces due to their mass too weak to keep them together
  • Strong nuclear force holds all nucleons together since both protons and neutrons are made up of quarks.
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9
Q

What is the range of a strong nuclear force?

A
  • Repulsive below 0.5 fm
  • Attractive up till 3.0 fm
  • Maximum attraction at 1.0 fm (typical nuclear separation
  • Becomes 0 after 3.0 fm
  • Has small range compared to other fundamental forces (only up to 3.0 fm)
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10
Q

What is alpha decay?

A
  • Common in large, unstable nuclei with too many protons
  • Involves nucleus emitting alpha particle (2 protons and 2 neutrons)
  • Proton number decreases by 2
  • Nucleon number decreases by 4
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11
Q

What is beta minus decay?

A
  • β- particle is a high energy electron emitted from the nucleus
  • neutron turns into a proton emitting an electron and an anti-neutrino
  • Proton number increases by 1
  • Nucleon number stays same
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12
Q

What is beta plus decay?

A
  • β+ particle is a high energy positron emitted from the nucleus
  • Proton turns into a neutron and a positron (anti-electron) and a neutrino
  • Proton number decreases by 1
  • Nucleon number stays same
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13
Q

What is a neutrino?

A
  • Type of subatomic particle with no charge and negligible mass which is also emitted from the nucleus
  • its existence was hypothesised to account for the conservation of energy in beta decay
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14
Q

What is antimatter?

A
  • Antimatter particles are identical to their matter counterpart but with the opposite charge
  • Still have identical mass and rest mass-energy (Rest mass-energy of a particle is the energy equivalent to the mass of the particle at rest)
15
Q

What is annihilation?

A
  • When a particle meets its equivalent anti–particle they both are destroyed and their mass is converted into energy in the form of two gamma ray photons
  • The minimum energy of one photon after annihilation is the total rest mass energy of one of the particles
  • To conserve momentum photons move in opposite directions
  • Mass and energy still conserved (as with all collisions)
16
Q

What is equation in annihilation?

A
  • E (minimum energy of photon) = h (planck’s constant = 6.63x10^-34) x f (frequency)
17
Q

What is pair production?

A
  • When a photon interacts with a nucleus or atom and the energy of the photon is used to create a particle–antiparticle pair (opposite of annihilation)
  • Means the energy of the photon must be above a certain value to provide the total rest mass energy of the particle and antiparticle pair
  • Minimum energy for a photon to undergo pair production is the total rest mass energy of the particles produced
  • To conserve momentum, the particle and anti–particle pair move apart in opposite directions
18
Q

How do you work out frequency?

A
  • Frequency = wave speed / wavelength
  • Wave speed is equal to speed of light (3x10^8) for gamma ray photons
19
Q

What does 1 electron volt equal?

A
  • 1.6x10^-19
  • So 1 Mev = 1.6x10^-13