The atomic nucleus was discovered by Earnest Rutherford in his Gold Foil Experiment in which he shot alpha particles at a thin piece of gold foil. Most of the particles went straight through the foil, but a few bounced straight back. This told him that there must be small compact positive units inside the atom. This is the atomic nucleus, a small core which contains most of an atom's mass but makes up only a 100,000th of the atom's total volume. The ratio of protons to neutrons in an atomic nucleus affects an atom's stability and can cause radioactive decay.
Understanding the structure and history of the atomic nucleus
This video describes Rutherford's (Geiger-Marsden's) discovery of the nucleus and the ideas that formed their hypothesis and the reformation of the atomic model from the results and its implications for further understanding of atomic structure
Nuclear stability is what makes certain isotopes radioactive. An isotope is unstable if it has a ratio of protons to neutrons that isnt within what is called the band of stability. Elements with atomic numbers greater than 70 are never stable. Unstable isotopes generally undergo transmutation, alpha decay, or beta decay.
How the ratio of protons to neutrons affects a nucleus' stability.
A good introductory video on nuclear stability.
Nuclear reactions are reactions between nuclei which involve tremendous amounts of energy and in which mass number and charge are conserved. Alpha and beta decay, fission and fusion are all types of nuclear reactions. Unlike chemical reactions, atomic number is usually changed.
The different types of nuclear reactions.
In nuclear physics, a nuclear reaction is the process in which two nuclei or nuclear particles collide to produce products different from the initial
Alpha Decay is a type of radioactivity in which the nucleus of an atom loses an alpha particle. Alpha particles are composed of two protons and two neutrons, so they can also be called He2+ nuclei. The result of alpha decay is the transformation of an element into an element found two boxes before it on the periodic table.
Understanding the alpha decay of radioactive substances.
Alpha decay is a type of radioactive (nuclear) decay. This video explains what alpha decay is, how atoms go from stable to unstable, and shows practice problems with examples of alpha decay.
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