Nuclear Chemistry Aim Nuke1 What is radioactivity?

1. Nuclear ChemistryAim Nuke1What is radioactivity?

2. A Brief History of Nuclear Chem • 1895 - Wilhelm Roentgen – German • discovered “X-rays”, a powerful form of electromagnetic energy • 1896 - Henri Becquerel - French • discovered radioactivity when he left uranium on top of photographic film • also suffered radiation burns from a sample of radium in his pocket

3. A Brief History of Nuclear Chem • 1898 - Henri and Marie Curie – French • using radiometry (the measure of electromagnetic energy strength and distribution) • separated uranium ore into different fractions • Discovered thorium, polonium (named for Poland, where Marie was originally from) and radium

4. A Brief History of Nuclear Chem • 1899 - Ernst Rutherford - English • showed that radioactive decay can be described by a simple equation • implying that a given radioactive substance has a characteristic "half-life" • the TIME taken for HALF THE AMOUNT of radioactivity present in a source to decay • He also coined the terms alpha particle, beta particle, and gamma rays • he converted nitrogen into oxygen (first example of artificial transmutation) • Theorized there were particles called neutrons

5. A Brief History of Nuclear Chem • 1932 James Chadwick • Discovers Rutherford’s neutrons through experimentation • He shot alpha particles through a beryllium sheet, and through a layer of wax • Detected protons at the end of the process

6. A Brief History of Nuclear Chem • 1938 Otto Hahn, Lise Meitner, and Fritz Strassmann • became the first to split uraniumatoms by bombarding them with neutrons • Measureable amounts of energy released • Coined the name fission, after binary fission in biology • Small nuclear reaction!

7. A Brief History of Nuclear Chem • 1939 Leo Szilard • Writes a letter with fellow scientists to President Franklin D. Roosevelt • Warns of the potential of fission as a potentially devastating weapon • Nazis in Germany were working already working on developing it • Albert Einstein signs the letter to add his support • Result • Roosevelt authorizes a small study into uranium. • US, UK, and Canada begin work on the atomic bomb

8. A Brief History of Nuclear Chem • 1942 Enrico Fermi • successfully created the first man-made nuclearchain reaction • Squash court under the stadium at the University of Chicago • Also almost created the first nuclear meltdown • On that same squash court • Meltdown • the nuclear material inside the reactor overheats • Melts through building • Heads toward China • Also called the “China Syndrome”

9. A Brief History of Nuclear Chem • 1939-1945 The Manhattan Project • a research and development project that produced the first atomic bombs during World War II. • July 16th, 1945 • Trinity Test at Los Alamos • First nuclear bomb test • Upon seeing the destructive power of the atomic bomb, Robert Oppenheimer, project leader, quotes the Bhagavad Gita, a Hindu text, saying: “Now I am become death, the destroyer of worlds”

10. A Brief History of Nuclear Chem • August 6th, 1945 • a uranium bomb, Little Boy, dropped on Hiroshima Japan • August 9th, 1945. • a plutonium bomb, Fat Man, dropped on Nagasaki, Japan on • The cities are devastated, with up to 250,000 people dead. • Japan surrenders unconditionally 6 days later, on August 15th, 1945. • Use of the atomic bombs ends World War II • US does not have to invade Japan, saving millions of lives both Japanese and Allied • Controversy still surrounds the decision to use the weapon even till today