Nuclear Chemistry in a Nutshell
Marie Curie Credited with the discovery of radioactivity! What is a radioisotope? FACT- Stable isotopes are only 17% of all isotopes... WHAT??? Radioisotopes: Atoms with unstable nuclei , radioactive decay (half lives) Like an isotope…. A nuclide is an atom with a specific number of p+ and n in the nucleus Ex: C-13 ? p+ and ? n
Types of Particles: ALPHA BETA GAMMA
Alpha and Beta Particles- explained Changes mass by 4 (equivalent to 2p+ and 2no) and atomic # by 2 Beta High energy e- ; increases atomic number by 1 however mass # doesn't change
Nuclear Decay Equations: This is an example of a decay equation: Alpha decay - see the alpha particle in the products? What type of decay is this one?
Try these. Write in A-Z isotope notation Try these! Write in A-Z isotope notation. Write reactants that I give you, ‘yields,’ products based on the type of decay. (a) C- 14 by beta decay (b) B - 8 by beta decay (c) I - 125 by alpha decay (d) Rn- 210 by alpha decay (e) gamma-ray emission by Ni- 56
Gamma radiation occurs in ALL decay!
Transmutation Transmutation (converting of one atom into another) occurs by Nuclear Decay Particle Acceleration – use an electromagnetic field to propel charged particles and “smash” them into each other CERN - ATOM SMASHER! In Switzerland
Fission and Fusion
To become more stable, atoms will undergo.... FISSION! A large nuclide breaks into smaller nuclides Releases LARGE amt of E, chain rxn, used in nuclear power plants to produce heat in nuclear reactors FUSION! small nuclides combine to form larger nuclides In the sun, H atoms fuse to make He nuclides, releases very LARGE amts of E!
Half Life Calculations Radioactive Dating: Half life (t1/2 ) Definition - The amount of time required for half of a radioactive sample to decay completely Ex. C-14 emits beta radiation and decays with a half-life of 5730 years. Assume you start with a mass of 2.00 x 10-12 g of C-14. How long is 3 half lives? How many grams of the original isotope remain at the end of 3 half lives?
Practice Example Ex. Manganese-56 is a beta emitter with a half-life of 2.6 h. What is the mass of Manganese-56 in a 1.0mg sample of the isotope at the end of 10.4h?