1. The nucleus and nuclear reaction

2. X C Atomic notation A Z 12 6 X = Symbol (C, Au)
A = Atomic Mass Number = #nucleons
(Protons + Neutrons)
Z = Atomic Number = #protons C 12 6
Carbon A = 12, Z = 6. #neutrons?

3. C C Isotopes 12 6 14 6 Carbon 12 has 6 Neutrons
Carbon 14 is an isotope of Carbon
Chemically the same
Nuclear-lly different (it’s unstable)
C-14, C-12

4. The whole is less than the sum of the parts!
The Mass Defect
The mass defect is the difference between the rest mass of a nucleus and the sum of the rest masses of its constituent nucleons.
Mass defect = actual (rest) mass of the nucleus – total mass of nucleons
The whole is less than the sum of the parts!

5. Mass-energy equivalence
Beyond the classical approximation, mass is actually part of the internal energy of an object or system with E = mc2. a. E = mc2 can be used to calculate the mass equivalent for a given amount of energy transfer or an energy equivalent for a given amount of mass change (e.g., fission and fusion reactions).

6. EB = (mass defect in u) (931.49 MeV/u)
The Binding Energy
The binding energy EB of a nucleus is the energy required to separate a nucleus into its constituent parts.
EB = (mass defect in u) ( MeV/u)

7. Binding Energy per Nucleon
An important way of comparing the nuclei of atoms is finding their binding energy per nucleon:
𝐵𝑖𝑛𝑑𝑖𝑛𝑔 𝑒𝑛𝑒𝑟𝑔𝑦 𝑝𝑒𝑟 𝑛𝑢𝑐𝑙𝑒𝑜𝑛= 𝐸 𝐵 𝐴

8. Conservation of nucleon number in nuclear reaction
The possible nuclear reactions are constrained by the law of conservation of nucleon number. Example: Beta decay Example: Alpha decay

9. Fission
When atoms are bombarded with neutrons, their nuclei splits into 2 parts which are roughly equal in size.
Nuclear fission in the process whereby a nucleus, with a high mass number, splits into 2 nuclei which have roughly equal smaller mass numbers.
During nuclear fission, neutrons are released.

10. Nuclear Fission There are 2 types of fission that exist:
1. Spontaneous Fission
2. Induced Fission

11. Spontaneous Fission
Some radioisotopes contain nuclei which are highly unstable and decay spontaneously by splitting into 2 smaller nuclei.
Such spontaneous decays are accompanied by the release of neutrons.

12. Induced Fission
Nuclear fission can be induced by bombarding atoms with neutrons.
The nuclei of the atoms then split into 2 equal parts.
Induced fission decays are also accompanied by the release of neutrons.

13. The Fission Process
A neutron travels at high speed towards a uranium-235 nucleus. U
235 92 n 1

14. A neutron travels at high speed towards a uranium-235 nucleus.
The Fission Process
A neutron travels at high speed towards a uranium-235 nucleus. U
235 92 n 1

15. A neutron travels at high speed towards a uranium-235 nucleus.
The Fission Process
A neutron travels at high speed towards a uranium-235 nucleus. U
235 92 n 1

16. The neutron strikes the nucleus which then captures the neutron.
The Fission Process
The neutron strikes the nucleus which then captures the neutron. U
235 92 n 1

17. The Fission Process
The nucleus changes from being uranium-235 to uranium-236 as it has captured a neutron. U
236 92

18. The uranium-236 nucleus formed is very unstable.
The Fission Process
The uranium-236 nucleus formed is very unstable.
It transforms into an elongated shape for a short time.

19. The uranium-236 nucleus formed is very unstable.
The Fission Process
The uranium-236 nucleus formed is very unstable.
It transforms into an elongated shape for a short time.

20. The uranium-236 nucleus formed is very unstable.
The Fission Process
The uranium-236 nucleus formed is very unstable.
It transforms into an elongated shape for a short time.

21. It then splits into 2 fission fragments and releases neutrons.
The Fission Process
It then splits into 2 fission fragments and releases neutrons. n 1
141 56 Ba n 1 92 36 Kr n 1

22. It then splits into 2 fission fragments and releases neutrons.
The Fission Process
It then splits into 2 fission fragments and releases neutrons. n 1
141 56 Ba n 1 92 36 Kr n 1

23. It then splits into 2 fission fragments and releases neutrons.
The Fission Process
It then splits into 2 fission fragments and releases neutrons. n 1
141 56 Ba n 1 92 36 Kr n 1

24. It then splits into 2 fission fragments and releases neutrons.
The Fission Process
It then splits into 2 fission fragments and releases neutrons. n 1
141 56 Ba n 1 92 36 Kr n 1

25. Nuclear Fission Examples
235 92 + Ba
141 56 n 1 3 Kr 36 U
235 92 + Cs
138 55 n 1 2 Rb 96 37

26. Nuclear Fusion H + He n Energy 2 1 4 3
In nuclear fusion, two nuclei with low mass numbers combine to produce a single nucleus with a higher mass number. H 2 1 + He 4 n 3
Energy

27. The Fusion Process H 2 1 H 3 1

28. The Fusion Process H 2 1 H 3 1

29. The Fusion Process H 2 1 H 3 1

30. The Fusion Process H 2 1 H 3 1

31. The Fusion Process

32. The Fusion Process

33. The Fusion Process

34. The Fusion Process

35. The Fusion Process n 1 He 4 2
ENERGY

36. The Fusion Process n 1 He 4 2
ENERGY

37. The Fusion Process n 1 He 4 2
ENERGY

38. The Fusion Process n 1 He 4 2
ENERGY

39. Structure of the nucleus
Fundamental particles have no internal structure. a. Electrons, neutrinos, photons, and quarks are examples of fundamental particles. b. Neutrons and protons are composed of quarks. c. All quarks have electric charges, which are fractions of the elementary charge of the electron.

40. The Standard Model

41. Table of elementary particles

43. Conservation of electric charge in nuclear reactions
Electric charge is conserved in nuclear and elementary particle reactions, even when elementary particles are produced or destroyed. Example: What is the charge of a particle that has the following quark components? a. uuu q = (+2/3 e) + (+2/3 e) + (+2/3 e) = 2e b. d 𝑠 q = (-1/3 e) + (+1/3 e) = 0