Timeline: Nuclear Treaties & Agreements

1963 Limited Test Ban TreatyAn agreement between the US, USSR, and UK which prevented nuclear testing above ground, underwater, and in outer space. But it does allow testing to occur underground as long as the radioactive fallout is not widespread. A total of 116 countries have signed this, and China, who had not signed, did testing in 1992 that violated the treaty's guidelines.

Chronological Developments in Nuclear Physics

1890s
1895
November 8 - Wilhelm Roentgen discovers X-Rays
1897
Becquerel and Marie Curie discover radioactivity
1895 - 1899
Ernest Rutherford discovers alpha and beta radiation
1898
Marie and Pierre Curie isolated the two new chemical elements polonium and radium

Atomic and Nuclear Physics

Atoms - Atoms are the smallest unit of an element that chemically behaves the same way the element does. When two chemicals react with each other, the reaction takes place between individual atoms at the atomic level.

Atomic Structure

• In the early 20th century, a New Zealand scientist working in England, Ernest Rutherford, and a Danish scientist, Niels Bohr, developed a way of thinking about the structure of an atom that described an atom as looking very much like our solar system.
• An atom is composed of three basic particles – electrons, protons and neutrons.
• Nucleus of an atom consists of protons and neutrons.
• Electrons revolve in atomic orbit.