Nuclear Chemistry Nuclear chemistry is the study of the structure of atomic nuclei and the changes they undergo.

Nuclear Reactions VS Chemical Reactions

Marie Curie 1876-1935 Polish scientist whose research led to many discoveries about radiation and radioactive elements. Won the Nobel Prize along with her husband in 1903 in physics for her work on radioactivity. Won the Nobel Prize in Chemistry in 1911 for research on radioactive elements.

Curium: An element named after Marie Curie Curium is a transuranic radioactive chemical element with the symbol Cm and atomic number 96. This element of the actinide series was named after Marie and Pierre Curie – both were known for their research on radioactivity.

Some Basic Information before the fun stuff… Marie Curie named the process by which materials give off such rays radioactivity. The penetrating rays and particles emitted by a radioactive source are called radiation. In nuclear reactions, the nuclei of unstable isotopes, called radioisotopes, gain stability by undergoing changes. = radioactive elements!

Defect of Mass Remember the Law of Conservation of Mass? Some of the mass can be converted into energy… Shown by a very famous equation! E=mc2 Energy = E Mass = m Speed of light = c

Radioactive Elements An unstable nucleus releases energy by emitting radiation during the process of radioactive decay. It is SPONTANEOUS. You do not have to input energy or force it. What types of things are being emitted?

Types of Radiation 1) Alpha Radiation: too many protons causes excessive repulsion. In an attempt to reduce the repulsion, a Helium nucleus is emitted.

Wait… You mean that DIFFERENT elements are being made? YEP! Transmutation: a change in the identity of the nucleus because of a change in the number of its protons.

Types of Radiation 2) Beta Radiation: neutron to proton ratio is too great in the nucleus and causes instability. Example:

Other Types of Beta: Positron Emission: neutron to proton ratio is too small. A proton turns into a neutron and a positron and the positron is emitted. Electron Capture: neutron to proton ratio in the nucleus is too small. The nucleus captures an electron which basically turns a proton into a neutron.

Types of Radiation 3) Gamma Radiation occurs because the nucleus is at too high an energy. The nucleus falls down to a lower energy state and, in the process, emits a high energy photon known as a gamma particle. 

Electromagnetic Radiation

So how dangerous is it? Depends on the type of radiation…

Half-Life HALF-LIFE is the time that it takes for 1/2 a sample to decompose.

Half-Life, t1/2 For example: Ra-234 has a half-life of 3.6 days If you start with 50 grams of Ra-234 1) After 3.6 days  25 grams 2) After 7.2 days  12.5 grams 3) After 10.8 days  6.25 grams

Half-Life 200

Nuclear Fission Nuclear Fission and Chain Reactions http://www.pbs.org/wgbh/nova/education/physics/fission-chain-reaction.html

Nuclear Fusion http://www.ted.com/talks/taylor_wilson_yup_i_built_a_nuclear_fusion_reactor

Radiation In Our Lives Detecting: Geiger counters. Scintillation Counter Film Badge

Applications: Radiation can produce ions, which can then be detected, or it can expose a photographic plate and produce images. Irradiation of Food: This scanned image of a thyroid gland shows where radioactive iodine-131 has been absorbed. Drinks a fluid containing small amount of radioisotope iodine-131. Thyroid extract the iodine from the blood stream to create a hormone.

Nuclear Magnetic Imaging/Resonance AKA Magnetic Resonance Imaging (MRI) Thyroid imaging using Tc-99m

The Bad:

Just In Case…

Summary This can help you study for the EOC! On Page 801 in your textbook.