1. Nuclear Physics

2. Discuss The following questions
With your neighbor
Intro:
Where do you find protons?
Where do you find neutrons?
Where do you find electrons?
How many protons does it have?
How many neutrons?
Is it a neutral atom, and how do you know?

3. The Atom In the nucleus Proton- (+) charged particle
Neutron- no charge
Outside the nucleus
Electron- (-) charged particle
has almost no mass

4. Nucleons Are subatomic particles inside the nucleus
Consist of + charged protons and neutral neutrons
Have almost 2000 times the mass of electrons
Because of the two types of nucleons, the nucleus is positively charged

5. Where can you find the number of protons?
It’s the atomic number (found on the periodic table)

6. B Nuclear Notation Atomic Number Atomic Mass 5 10.811
Atomic number = no. of protons
Atomic mass = protons + neutrons (total number of nucleons
In the nucleus)
Atomic number is the same as the number of electrons
in an uncharged atom

7. Question 1 1a. How many protons? 1b. How many neutrons?
You may see atomic number written many ways. The smaller number is the atomic number and the larger is the atomic mass
1a. How many protons?
1b. How many neutrons?
1c. How many nucleons?

8. has 13 protons and 14 neutrons for a total of 27 nucleons
The identity of an element depends on the number of protons
What do you notice that is different between the two Aluminum atoms? 28 13

9. Isotopes:
Atoms of the same element with different numbers of neutrons (giving them different masses)
Most common stable isotope of carbon
Unstable radioactive isotope of carbon

10. Review of Fundamental forces
Strongest to weakest
Strong Nuclear Force
Electromagnetic Force
Weak Nuclear Force
Gravity

11. 2 Forces Acting on Nucleons:
Forces of attraction between nucleons
Strong forces
Holds the nucleons in the nucleus
Are independent of the charge of the nucleon
Are short range (exist only between closest neighbors)
Electrical force (electrostatic)
Force of repulsions between positively charged protons
Are long range

12. When are nuclei stable/unstable?
When there is an equal number of protons and neutrons
Unstable:
Large nuclei – electrical forces of repulsion are greater than strong forces of attraction
All elements after Bismuth (Bi #83) are considered unstable and therefore naturally radioactice

13. A radioactive isotope:
Has an unstable nucleus
Spontaneously emits a particle and decays into another element (to become more stable)

14. Transmutation
Changing into another element through radioactive decay

15. Types of Radioactive Emission
Symbol
Composition
Stopped By
Alpha
2p + 2n (helium)
Paper
Beta
1e (electron)
Aluminum
Gamma γ
Energy only
Lead

16. Alpha Decay
Radiation through the loss of 2p + 2n or (helium)

17. Beta Decay
Radiation where a neutron splits, giving off an electron and becoming a proton in the new element

18. Beta Decay

19. Beta Decay: Electron Capture
The capture of the electron allows the proton to turn into a neuron.

20. Gamma Decay A change energy state gives off a gamma particle or photon
Electromagnetic radiation

21. Question 3a
Balance the nuclear equation after alpha decay

22. Question 3a
Balance the nuclear equation after alpha decay

23. Question 3b Balance the nuclear equation after beta decay
Remember in beta decay a neutron changes into a proton by giving off an electron

24. Question 3b Balance the nuclear equation after beta decay
Remember in beta decay a neutron changes into a proton by giving off an electron

25. Quiz Grade Page 626 Define all key terms Review Questions: 1-10
Think and Explain Questions: 29, 30, 41, 41, and 45

26. Extra Question
Which radioactive isotope completes this nuclear decay equation 6

27. Extra Problem
Finish off the equation

28. Show what you know

33. Warm-up Questions
An element decays multiple times, emitting 2 alpha particles and 1 beta particle. What happens to its atomic number?
The nucleus of an atom consists of…
The force that holds the nucleus together is the ___________ force.
If 1/8 of a sample is left and it has a half life of 1 billions years, what is the samples age?
An alpha particle consists of…
If a radioactive material has a half life of 3 year, what percentage would be left after 3 years?

34. Nuclear Fission
Nuclear fission - Heavy nuclei are bombarded with neutrons and split.
plus a tremendous amount of energy

35. Nuclear fission
Mass of particles produced is slightly less than the mass of the reactants. This mass is converted into energy. (E=mc2)

36. Nuclear fission is a chain reaction
Nuclear fission is a chain reaction. Neutrons are needed to start and released as a product which can start more reactions.
Critical mass: minimum mass of fissionable material required for a chain reaction.

37. Problems with Fission
Nuclear fission produces radioactive waste that has a large half life.
U Uranium 235
Half life of U-235 is 713 million years
We cannot get rid of this dangerous product so we store it away from anything it can harm.
We deeply bury
Meltdown if cooling system fails the reactor can overheat and melt releasing radioactive materials

38. Nuclear fusion – combination of small nuclei into larger with release of energy.
Mass of particles produced is much less than the mass of the reactants.
This mass is converted into energy. (E=mc2)
Can release up to 10 times that of fission
Occurs naturally in our sun and other stars
Does not give off radioactive waste

39. Problems with Fusion
Fusion requires high temperatures like those in the stars.
We cannot sustain these temperatures without vaporizing the container of the fusion reaction.
Today many are looking into ways of making fusion work under sustainable conditions