Nuclear Chemistry

Radioactivity  Radioisotopes – isotopes that are unstable, who’s nucleus undergoes changes to gain stability  Radiation – the penetration of rays and particles emitted by a radioactive source  Radioactive Decay – when an unstable nucleus loses energy by emitting radiation

Types of Radiation  Alpha Radiation  Consist of helium nuclei that have been emitted from a radioactive source  Emitted particles are alpha particles, which contains 2 protons and 2 neutrons

Types of Radiation  Beta Radiation  Consists of fast moving electrons formed by the decomposition of a neutron in an atom  Beta particles have less charge and less mass than alpha particles. What does this mean?

Types of Radiation  Gamma Radiation  High – energy electromagnetic radiation  Gamma rays are often emitted along with alpha or beta radiation by the nuclei of disintegrating radioactive atoms

Video Clips  Radioactivity Radioactivity  Marie Curie Marie Curie Marie Curie  Ions Ions

Half - Life  A half-life (t 1/2 ) is the time required for one-half of the nuclei of a radioisotope sample to decay to products  Read pg Read pg Read pg 

Transmutation Reactions  Transmutation – is the conversion of an atom of one element to an atom of another element.  1 – transmutation through decay  2 – transmutation through altering the amount of protons or neutrons in the nucleus

Transmutation Reactions  The elements which have an atomic number greater than 92, are not naturally occurring elements. These elements are called transuranium elements

Radioactive Series  Large radioactive nuclei cannot stabilize by undergoing only one nuclear transformation.  They undergo a series of decays until they form a stable nuclide (often a nuclide of lead).

Nuclear FusionNuclear Fission Fusion is the fusing of two or more lighter atoms into a larger one. Fission is the splitting of a massive atom into two or more smaller ones. High density, high temperature environment is required. Critical mass of the substance and high-speed neutrons are required. Extremely high energy is required to bring two or more protons close enough to fuse. Takes little energy to split two atoms in a fission reaction. Fusion occurs in stars, such as the sun. Fission reaction does not normally occur in nature.

Nuclear Fission  Neutrons released in the transmutation strike other nuclei, causing their decay and the production of more neutrons.

Nuclear Fission This process continues in what we call a nuclear chain reaction.

Nuclear Fusion  Fusion would be a superior method of generating power.  The good news is that the products of the reaction are not radioactive.  The bad news is that in order to achieve fusion, the material must be in the plasma state at several million kelvins.  Fusion / Fission video Fusion / Fission video Fusion / Fission video  Video 2 Video 2 Video 2