1. ttp://www.youtube.com/watch?v=NNcQX033V_M&NR=1&feature=fvwp http://www.youtube.com/watch?v=zLFRIiflSgU&feature=related Nuclear Chemistry

2. LecturePLUS Timberlake2 Review - Atomic Symbols Show the mass number and atomic number Give the symbol of the element mass number 23 Na atomic number 11 Sodium-23 Protons + Neutrons Protons

3. LecturePLUS Timberlake3 Review - Isotopes Atoms with the same number of protons, but different numbers of neutrons. Atoms of the same element (same atomic number) with different mass numbers Isotopes of chlorine 35 Cl 37 Cl17 chlorine - 35 chlorine - 37

4. Radiation Radioactive Decay - When nuclei are unstable (due to an unfavorable ratio of neutrons to protons) they throw off particles and energy to become more stable.

5. What is the significance of the number of neutrons? In atoms with a low atomic number, stable isotopes have N (# of neutrons) = Z (# of protons). As atomic number increases, it takes more neutrons (N) to be stable. All atoms with an atomic number > 82 (lead) are radioactive.

6. Nuclear Decay reactions There are Three Main Types of Radioactive Decay 1.Alpha ( ) Decay 2.Beta ( ) Decay 3.Gamma ( ) Decay Nuclear Reaction: Any reaction in which the particles that make up the nucleus (protons and neutrons) are rearranged to form a different element or isotope.

7. Nuclear Decay reactions Alpha Decay: When an element is broken down in alpha decay it emits 2 neutrons and 2 protons. Alpha decay is the most common in elements with an atomic number greater than 83.element symbol: (alpha particle) = or alpha particle is the same as a Helium nucleus Write the alpha decay of U-235.

8. Nuclear Decay Reactions Example: Alpha emission Note that mass number (A) goes down by 4 and atomic number (Z) goes down by 2. Nuclear particles (protons and neutrons) are rearranged but conserved (not created or destroyed) He

9. Properties of an Alpha Particle Relatively large Positively charged (2+). It has very low penetration and can be shielded by a thin piece of paper.

10. Nuclear Decay Reactions Beta Decay : When an element is broken down in beta decay a neutron converts to a proton and an electron is emitted.element Beta emission increases the atomic number by one, but the mass stays theatomic number same. Symbol: (beta particle) = or Beta decay is most common in elements with a high neutron to proton ratio. Write the beta decay of sulfur-35

11. Properties of a Beta Particle Relatively small with very low mass Negatively charged (1-). A beta particle is much more penetrating. It can be shielded by a layer of lead.

12. Gamma Decay: In gamma emission, there is no change in the atomic number or the mass number. Gamma rays are NOT particles, but a high-energy photon of light. A high-energy gamma ray is given off when the parent isotope falls into a lower energy state. Symbol: or They often accompany nuclear decay of other type. Example: Nuclear Decay Reactions

13. Penetrating Ability

15. Effects of Radiation Rem or Rad is the biological effect of radiation It is related to the strength of the radiation as well as the damage it causes

16. Geiger Counter Used to detect radioactive substances Click the pictures

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

18. Each time a fission occurs, large amounts of energy are released Under certain conditions a chain reaction is started that creates a HUGE amount of energy to be released very quickly!

19. They have found a way to tap the energy in nuclear reactions in a controlled way. http://www.msnbc.msn.com/id/42029294/ns/technology_and_science-science/t/how-nuclear-plant-works/ Link to Animation

20. Nuclear Fusion Energy Fusion – perfect, but difficult small nuclei combine to create larger atoms 2 H + 3 H 4 He + 1 n + 1 1 2 0 Occurs in the sun and other stars

21. Energy and Mass When a nuclear reaction occurs, there is a mass loss. This mass is called the “mass defect” and is the result of mass being converted to energy. The energy can be calculated from the mass by Einstein’s famous equation: E = mC 2 E is energy in joules, m is mass defect in Kg C is speed of light 3.0 x 10 8 m/s

22. Energy and Mass What is the total energy in one mole of Carbon atoms? One mole of Carbon atoms has a mass of 12.01 grams E = mC 2 E =.01201 kg x (3.0 x 10 8 m/s) 2 = 1.08 x 10 15 Joules Roughly the annual output of the Grand Coulee Dam in eastern Washington!