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Properties of the Nucleus, Particle Equations, Types of Radiation,…

- - - - mass number
        
        how many nucleons there are in the atom
        
        protons and neutrons essentially have the same mass
        
        these represent the relative mass of each nucleus
      - numbers on the left must add up to the right
    - - atomic number
        
        show the number of protons in each nucleus
        
        represent the charge of each nucleus
      - numbers on the left must add up to be the same for the right
  - - - essentially massless
        
        charge is opposite a protion
        
        1
        
        mass = 0
- - - - Nuclear Decay
      - Nuclear Fission
      - Proton/Neutron Capture
- - - - :arrow_right: replaces =
      - Everything uses the standard notation for isotopes
- - - - How much it takes them to stop travelling through stuff
  - - - Ability to alter chemicals (such as body tissues
  - - - Least penetrating of the three
        
        can be stopped by a sheet of paper
      - Most ionising of the three
        
        can cause the most damage to the tissues in your body
      - Range is several centimetres
    - - Less ionising than alpha particles
        
        cause less damage to your tissues
      - More penetrative than alpha particles
        
        stopped by a sheet of metal
      - range through air is several metres
    - - Most penetrating of the three
        
        stopped by atleast a few centimetres of lead
      - Least ionising of the three
        
        Causes the least damage to tissues
      - Range through air is boundless
        
        many many metres
  - - - Radiation that penetrates more ionises less and vice versa
        
        If the radiation is a stronger ioniser then it bumps into lots of atoms and can't travel as far
        
        If radiation penetrates further then it doesn't stop to ionise atoms
- - - - same as helium nucleus
        
        two protons and two neutrons
        but no electrons
    - - just an electron
    - - type of EM radiation
        
        High frequency
        
        Small Wavelength
- - - - I = intensity
        
        how many EM waves are in an area at any time
        
        d = distance from source
    - - If distance doubles
        
        intensity drops by a factor of four
      - If distance quadruples
        
        intensity drops by a factor of 16
- - - - will be written as an atoms standard notation
    - - symbol
      - atomic number
      - mass number
  - - - alpha particle decay
        
        atom will emit two protons and two neutrons as an alpha particles
  - - - forces between nucleons aren't strong enough to hold it together
        
        hence, becomes unstable
- - - - Only need to find remaining atom
        
        Method 1
        
        Equate the left and right hand side
        
        Example
        
        RHS = x + 4
        
        x = 204
        
        Same for atomic number
        
        Use atomic number to find element
        
        LHS = 208
        
        Look at the atomic and mass numbers
        
        Method 2
        
        Think about the decaying element
        
        Follow the decay process
        
        alpha decay means losing two protons and neutrons
        
        subtract mass number by 4
        
        subtract atomic number by 2
  - - - when there are too many neutron one breaks down
        
        neutron splits up into a proton and an electron
        
        proton stays in the atom
        
        electron is emitted as beta decay
      - Anti-neutrino
  - - - small atoms
        
        any number larger than the number of protons
      - large atoms
        
        more than 1.5 times the number of protons
- - - - Relative to number of neutrons
      - Protons are positively charged so they repel one another
        
        force becomes so strong it manages to break apart nucleus
  - - - Too many protons so one splits apart
        
        into a
        
        neutron
        
        anti-electron
        
        positron
        
        same as an electron but with a positive charge
      - Neutron stays in the atom
      - Positron is emitted as beta+ decay
        
        Neutrino
  - - - Think about the decaying element
        
        loses a proton
        
        gains a neutron
      - Follow the decay process
- - - - Just requires us to know no. of protons and nucleons
- - - - Isotopes close to this line are the most stable
    - - As the nucleus gets bigger it needs a larger number of neutrons per proton to maintain stability
      - shows ideal
        neutron:proton ration
    - - Once nucleus reaches a certain size it is simply too big to be stable
  - - - Alpha Decay - nucleus is too large
        
        Beta Decay - too many neutrons
        
        Beta+ Decay - too many protons
      - Goal of radioactive decay is to stabilise the isotope
        
        the corresponding decays more the specific isotopes more stable
- - - - Atom loses 2 protons and neutrons
      - isotope moves down and to the left
        
        this move the isotope closer to the stability line
    - - Atom loses a neutron and gains a proton
      - Isotope moves down and to the right
        
        closer to stability line
    - - atom gains a neutron and loses a proton
      - isotope moves up and to the left
        
        closer to stability line
- - - - cannot predict which will decay first in a group
      - if we observe a group of nuclei as it is decaying we can spot a pattern
        
        pattern shows the number of nuclei decaying per second is proportional to size of sample
        
        larger group of unstable nuclei has more decaying nuclei per second than a smaller group
        
        number of atoms
        
        decay constant
        
        3 more items...
        
        number of nuclei decreases over time
        
        change over the number of atoms over time
        
        equals the negative number of atoms multiplied by the decay constant
  - - - Activity
  - - - nuclei that decays faster will have:
        
        higher decay constant
        
        higher activity
- - - - Number of unstable nuclei
      - Initial Amount
      - Decay Constant
      - Elapsed time
  - - - Activity of Sample
        
        Initial Activity
        
        Decay Constant
        
        Elapsed Time
    - - similar to unstable nuclei remaining
  - - - Half-life
        
        Also unique for each isotope
        
        Decay Constant
        
        Unique for each isotope
        
        Isotopes which decay faster w/ greater constant have shorter half lives
- - - - this can give us a lot of energy
      - Large nuclei can also undergo fission on their own
        
        spontaneous fission
  - - - greater than
        
        Ending Mas
      - mass difference
        
        mass lost is converted into large amounts of energy
- - - - Releases a lot of energy
  - - - Nuclei are positively charged
        
        high temperatures provide energy to overcome the repulsion
    - - Lot of atoms in one area
        
        Higher chance of collisions to start the fusion reaction
- - - - Binding Energy
        
        Energy required to break apart the nucleus
      - Binding Energy per Nucleon (BEPN)
        
        How much energy we give each nucleon to split the nucleus apart
        
        Higher means that each nucleon is missing more energy
        
        Moving from a lower binding energy per nucleon to a higher one means the nucleons lose energy
        
        Energy lost is released
        
        Missing energy comes from the lost mass
      - Peak is at iron-56
        
        really stable nucleus
      - Fission and Fusion
        
        Fusion happens to left of peak
        
        Fission happens to the right
      - Energy needs to be released for a reaction to happen
        
        fusion moves nuclei to the right
        
        fission moves nuclei to the left
        
        A larger increase in BEPN releases more energy
        
        Fusion releases more energy than fission
- - - - Will be split up into
        
        proton
        
        Electron
        
        emitted as beta - particles
        
        Stays in the atom
      - Releases an antineutrino
  - - - Splits up into
        
        Neutron
        
        stays in the atom
        
        Anti-electron/positron
        
        emitted as beta+ particle
      - Releases a neutrino
- - - - Noticed that momentum wasn't conserved
      - Starting energy > ending energy
    - - Used conservation laws to know more about it
        
        Energy and Momentum weren't conserved
        
        some electrons were released with different energies
        
        Subatomic Particle has to exist
        
        Conservation of Mass
        
        Essentially massless
        
        Conservation of Charge
        
        Chargeless
- - - - m = mass
        
        kg
        
        c = speed of light
        
        E = Energy
        
        J
      - Shows that
        
        Conservation of Energy and Mass are the same thing
- - - - Mass Difference
        
        As the particles making the nucleus comes together, the total mass :arrow_down:
        
        mass decrease is converted to energy
      - Mass Defect
      - Mass Deficit
    - - Breaking up the nucleus requires energy
        
        This is binding energy
        
        Binding energy is converted into the extra mass
        
        equivalent to the mass difference
        
        Binding energy per nucleon
        
        Binding energy is divided by the number of nucleons
        
        Useful for comparing relative binding energies of differently sized nuclei