The study of nuclear change. Nuclear Chemistry The study of nuclear change. Some elements undergo chemical changes in their nucleus that alters their number of protons or neutrons.

Nucleus nucleus contains nucleons atomic mass, a.k.a. mass number p+ and n0 atomic mass, a.k.a. mass number protons + neutrons atomic number # protons identifies the element

Isotopic notation Symbol Mass Atomic number Symbol - Mass

U-242 U-232 U-236 U-234 U-239 U-238 U-240 U-235 U-229 U-235 U-238

An element is considered radioactive because it releases Energy Transmutation Sometimes the changes in the nucleus are such that an element is transformed into a different element change in atomic number An element is considered radioactive because it releases Energy during transmutation

Artificial Natural Transmutation Transmutation Change in nucleus occurs when bombarded by an alpha particle or neutron MUST be a reactant Change in nucleus occurs spontaneously The ONLY reactant is the atom undergoing transmutation

FYI . . . Since 1940, 23 transuranium elements have been formed All elements with atomic numbers > 93 were synthesized by nuclear reactions Glenn Seaborg created 10 of these elements atomic # 94 - 103 Element #106 was named for him Seaborgium

Stability of Nuclei Most nuclei are stable some elements have unstable isotopes Radioisotopes / nuclide Ex. C-12 stable and won’t transmutate C-14 unstable and will transmutate

What causes instability? As atoms increase in size the ratio of neutrons to protons also increases the larger the ratio the more unstable the atom Ex. compare C-14 to U-238 All nuclei with atomic numbers > 83 are unstable and radioactive

Unstable nuclei stable nucleus will spontaneously decay in order to form a stable nucleus

Types of Radiation Types of radiation emitted from the nucleus during transmutation alpha particles He or α beta particles ß- or gamma radiation γ Positrons β+ or 4 2

Radiation Penetration

How does Radiation affect cells? Radiation has the ability to ionize atoms Ionizing radiation causes damage to tissues by damaging molecules Most damaging is alpha; least is gamma Damage to proteins & DNA are most damaging If radiation exposure is low the body may repair itself If exposure is high, cells may die or cellular instructions might get “scrambled”

Radioisotopes are used in diagnosing and treating cancer diagnose thyroid disorders Co-60 treat cancer Short half lives decay quickly

Alpha Decay Alpha particle has to be a product.

Beta Decay A Beta particle has to be a product

Gamma Radiation Type of electromagnetic radiation like an x-ray No charge, no mass, no equations!

These 3 types of radiation were discovered by Rutherford

Positron Radiation

The End