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Radioactivity by Mind Map: Radioactivity

1. Conservation

1.1. nucleon number

1.2. proton number

1.3. mass-energy

2. Fundamental particles

2.1. not consist of combinations of other particles

2.2. e.g. lepton (electron)

3. Weak interaction between quarks

3.1. The role of it in the transmutation of quarks makes it the interaction involved in many decays of nuclear particles which require a change of quark from one flavor to another. Neutrino interaction induces beta decay.

4. Matter and antimatter

4.1. If a particle collides with its antiparticles, they annihilate each other, producing photons.

5. Subatomic particles

5.1. Hadron

5.1.1. composed of quarks, particles affected by strong nucleus force, subject to strong and weak force, bulky

5.1.1.1. meson: 2 quarks -> quark and antiquark

5.1.1.2. baryon: 3 quarks

5.1.1.2.1. proton: baryon number: +1

5.1.1.2.2. neutron: baryon number: +1

5.2. Leptons

5.2.1. particles that are unaffected by strong nuclear force, subject to weak force, light

5.2.1.1. neutrinos

5.2.1.2. electron

5.2.1.3. muon

5.2.1.4. tau

5.2.2. charge: -1

5.2.3. fundamental particle

6. quark

6.1. + 2/3 e

6.1.1. up, u

6.1.2. charm, c

6.1.3. top, t

6.2. - 1/3 e

6.2.1. down, d

6.2.2. strange, s

6.2.3. bottom, b

7. For reaction to occur

7.1. they must have same charge, baryon number (B) and electron lepton number (Le)

8. Alpha particle scattering experiment--Rutherford

8.1. 1. most alpha particles go through foil in straight line.

8.1.1. most of the atom is empty space

8.2. 2. some alpha particles were deviated with angles less then 90 degree.

8.2.1. nucleus takes positive charge

8.3. 3. only a few alpha particles were deviated with large angles greater than 90 degess.

8.3.1. mass and charge of atom concentrated in a small volume

9. Simple model of nuclear atom

9.1. proton and neutron in the nucleus and electron around the nucleus

10. Isotopes

10.1. Atoms of the same element that have same proton number but different number of neutron.

11. Representation of nuclides

11.1. Nuclides: special combinations of protons and neutrons

12. Radiation

12.1. Total number of nucleons remains constant as does the total number of mass of the nucleus is converted to energy of the emitted radiation--mass-energy conservation

12.1.1. Alpha

12.1.1.1. Helium nucleus contains 2 protons and 2 neutrons

12.1.1.2. strong ionising power, but short range, only can travel few cm in the air

12.1.1.3. positively charged

12.1.1.4. daughter particle has less mass than original particle before emitting radiation --> mass lost has been converted into energy as the source of kinetic energy of alpha particle. the total mass-energy is conserved.

12.1.1.5. a few cm in the air, stopped by a few sheets of paper

12.1.1.6. equations

12.1.2. Beta

12.1.2.1. Beta-

12.1.2.1.1. neutron in the nucleus changes into a proton and a high energy electron which is emitted

12.1.2.1.2. mass number stays the same, proton number increases by 1

12.1.2.1.3. A very light, electrically-neutral antiparticle called antineutrino is also emitted. conservation of electric charge required this particle to be electrically neutral

12.1.2.1.4. equations

12.1.2.2. Beta+

12.1.2.2.1. when a proton decays into a neutron and a high energy positron and electron neutrino.

12.1.2.2.2. mass number stays the same, proton number decrease by 1

12.1.2.2.3. equations

12.1.2.3. around 1 m in the air, stopped by several mm of aluminium

12.1.3. Gamma

12.1.3.1. high energy electromagnetic radiation

12.1.3.2. nucleus changes shape into a more stable shape, gamma radiation (gamma ray) emitted as a result

12.1.3.3. gamma decay can occur alongside alpha and beta decay, when an unstable nucleus adjusts to a more stable energy level.

12.1.3.3.1. mass-energy is conserved in nuclear reaction, energy might be released by gamma rays when sum of the masses on the left-hand side of the equation is not the same as right-hand side.

12.1.3.4. not affected by electric and magnetic fields

12.1.3.5. unlimited range in air, stopped by several cm of lead

12.1.3.6. equations

13. Distinguish between nucleon number and proton number

13.1. proton number=nucleon number -neutron number=electron number

13.2. nucleon number = atomic mass number

14. Deflection in electric field

14.1. alpha and beta particles are deflected in opposite directions in the uniform electric field, but gamma rays are undeflected as they have no charge

14.2. the force on an alpha particle is twice as large as the force on an electron moving at the same speed.

14.3. but the deflection of the alpha particle is much smaller due to its much larger mass