nuclearphysicsidk

1. bohr’s model of the atom §

more like whore’s model of the adam

• the bohr model of the atom describes the atom as consisting of a tiny positively charged heavy core, called a neutron.
• the heavy neutron is surrounded by negatively charged electrons revolving in circular orbits.

2. atomic number, mass, protons and neutrons. §

atomic number

• the number of protons

mass

• the weight of the atom (usually the number of protons and neutrons)

protons

• positively charged, located in the centre of the atom (nucleus).

neutrons

• no charge, located in the centre of the atom (nucleus).

3.1 strong nuclear force and electromagnetic force. §

Strong Nuclear Forces. §

Electromagnetic Forces. §

3.2. nucleons & radioactive decay. §

5. Alpha, Beta, Gamma Particles §

Alpha Particle §

• Symbol: ${}_2^4\alpha$ or ${}_2^{4}He$
• Mass: 4
• Speed: slow
• Ionising ability: High
• Stopped by: paper
• Atomic Number decreased by 2
• Atomic Mass decreased by 4

Beta Particle §

• Symbol: $\beta$ or ${\beta }^{-}$
• Mass: $1/2000$
• Speed: fast
• Ionising ability: Medium
• Stopped by: aluminium
• Atomic Number increase by 1
• Atomic Mass unchanged.

Gamma Particle §

• Symbol: $\gamma$
• Mass: 0
• Speed: very fast (speed of light)
• Ionising ability: 0
• Stopped by: lead
• Atomic Number & Mass unchanged.

Ionisation §

Ionisation, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion.

fission and fusion §

• the total mass of a stable nucleus is always less than the masses of the constituent protons and neutrons.
  • a little bit “illogical”, does not match the law of conservation of mass.
• there is a certain energy required called the “binding energy” that binds protons and neutrons together.
  • this energy makes up a small portion of mass, which makes up the difference between the weight of individual objects and the mass of all objects together.
  • difference in mass is considered to be the binding energy between individual nucleon/nucleus.
  • binding energy represents the amount of energy that must be must into the nucleus to break it apart into its individual nucleus.
• E=mc^2
  • energy is measured in joules
  • mass is measured in g
  • c is the speed of light, which is $3\times 10^{8}m/s$
• nuclei with a large binding energy per nucleon are most stable.
• smaller nuclei will undergo fusion to become more stable.
• larger nuclei will undergo fission to become more stable.
  1. 92, 36

Fission and Fusion §

Fission §

• Fission is the splitting of large nuclei to form smaller ones.
• Often initiated by neutron capture.
• Release large amount of energy.
• Often involves release of gamma photons and free neutrons.
• Nuclear Decay Chain Reaction
  • One neutron causes the nuclei to release smaller neutrons, which is absorbed by another large nuclei which creates a further fission reaction.

${}_{92}^{235}U{+}_0^{1}U$ → ${}_{56}^{141}$

Fusion §

• Fusion is the combining of smaller nuclei to form larger ones
• Releases a massive amount of energy
• Usually releases neutrons or protons as well as new nucleus
• Requires a huge amount of energy to take place

5.5 §

1. 1. 3n
   2. 3n
   3. 3n
2. 1. 239
   2. 40
3. B
4. D
5. 1. 195.2 MeV & 3.13 * 10^-11
   2. 20 times more than the highest energy released
6. A cobalt 60 nucleus will decrease inmassby 2.371 * 10^-30
7. Bombarding particle was Helium
8. 1. 5 * 10^27 kg of energy is lost
   2. 4.5 * 10^-11 J
   3. 1.25%
   4. 0.625 Kg
9. 1. 2.121 * 10^-26
   2. 9
   3. 3.14 * 10

Nuclear Power Stations §

• REMEMBER: common isotopes used by humans are uranium-238 and uranium-235.

• uranium-238 and uranium-235 have long half-lives.

• neutrons released from fission travels at high speeds.

  • these emitted neutrons need to be slowed down.

• parts of a nuclear power station - fuel rods - contains uranium - moderators - slows down neutrons - control rods - controls number of neutrons in the reaction - coolant - absorb some of the heat energy - radiation shield - prevents neutrons from escaping the reactor.

  5.7 questions

1. b
2. d
3. 1. a neutron is released during the chain reaction.
      1. the neutron is slowed down by a moderating material, which enables it to be absorbed by a. further uranium-235 nucleus.
      2. rate of reaction is controlled by raising or lowering the control rods. by lowering the control rods further into the core, it reduces the absorption of neutrons or stops the chain reaction.
      3. heat energy is removed from the core by pipes that contain a coolant. liquid sodium, water, carbon dioxide gas and heavy water are commonly used as coolants.
   2. a nuclear power station is more complex than coal-burning power stations, which only requires the burning of coal to generate electricity. the primary distance is that nuclear power station is much more environmentally friendly, but in exchange, it is a more complex technology.

• Unregulated cell growth through unregulated mitosis occurs when the DNA is altered after radiation leakage. This causes different kinds of deformities.

Arguments for and against the usage of nuclear energy and production. §

Pros §

• Nuclear Energy Saves Lives
  • Has prevented around 1.8 million deaths
  • Compared to other energy sources, there are relatively less deaths.
  • Reduces cancer, lung diseases and similar types of deaths caused by coal-powered stations.
• Nuclear Energy reduces $C{O}_2$ emissions.
  • Reduces greenhouse gas emission.
  • Energy consumption is increasing, and by increasing nuclear energy, this increased energy consumption’s effect of rapid climate change would be reduced/dampened.
• New Technology
  • The nuclear reactors used so far are old.
  • A proposed option to nuclear power creation, Thorium was suggested to be used.

Cons §

• Nuclear weapon production.
  • Nuclear weapon production are linked with the production of nuclear energy.
  • If there was no nuclear reactors, there would be no nuclear weapons.
• Nuclear waste and production
  • Spent nuclear fuel is radioactive and contains poisonous products. E.g plutonium, which takes tens of thousands of years to decay.
• Accidents and disasters
  • Over the years, 7 accidents happened, and 4 of them released large amounts of waste into the outside.