Marie Curie discovered radioactivity through her work on atoms and their structure. Nuclear reactions involve changes to the nucleus through loss of particles and rearrangement of protons and neutrons, releasing tremendous energy. There are three main types of radiation emitted in radioactive decay: alpha, beta, and gamma. Half-life refers to the time it takes for half of a radioactive sample to decay and is used in radioactive dating. Radiation is dangerous because it can ionize atoms and damage DNA, disrupting cells.

1. Nuclear Chemistry

15. Half Life The time required for half of the nuclei in a sample of a specific isotope to undergo radioactive decay.

16. Half Lives for Radioactive Elements Radioactive Parent Stable Daughter Half life Potassium 40 Argon 40 1.25 billion yrs Rubidium 87 Strontium 87 48.8 billion yrs Thorium 232 Lead 208 14 billion years Uranium 235 Lead 207 704 million years Uranium 238 Lead 206 4.47 billion years Carbon 14 Nitrogen 14 5730 years

17. Half Life and radioactive dating

18. Half-Life Decay of 20.0 mg of 15 O. What remains after 3 half-lives? After 5 half-lives?

22. Why radiation is dangerous Radiation ionizes atoms in cell tissue and causes chemical reactions akin to decomposition / combustion. disrupts nucleotide sequences (your DNA is mutated)

23. Why radiation is dangerous

27. Dosage in REMS Biological Effect : 25 notable change in blood cell components 100 radiation sickness - nausea, vomiting, decrease in white blood cell count, diarrhea, dehydration, prostration, hemorrhaging and loss of hair 200 the same as above but more pronounced in a shorter period of time 400 ½ of any population exposed to this dosage will be dead in 60 days 600 all exposed to this level will be dead in one week

29. Chernobyl Anyone near the Chernobyl plant when it melted down received 400 rems also immediately. The day after 1 rem/hr was found in the nearest city. Normal background radiation is 1,000 times lower than this

31. Detecting radiation

32. Detecting radiation

34. Nuclear Fuel Uranium “Yellow Cake” U 3 O 8

35. Fission Neutron

36. Fission Chain Reaction

37. Representation of a fission process.

38. Nuclear Fission

39. Diagram of a nuclear power plant.

49. Nuclear Medicine: Imaging Thyroid imaging using Tc-99m