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The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.
The Klein paradox, [46] discovered by Oskar Klein in 1928, presented further quantum mechanical objections to the notion of an electron confined within a nucleus. Derived from the Dirac equation , this clear and precise paradox suggested that an electron approaching a high potential barrier has a high probability of passing through the barrier ...
The nucleus was the first organelle to be discovered. What is most likely the oldest preserved drawing dates back to the early microscopist Antonie van Leeuwenhoek (1632–1723). He observed a "lumen", the nucleus, in the red blood cells of salmon . [ 97 ]
Scientists eventually discovered that atoms have a positively charged nucleus (with an atomic number of charges) in the center, with a radius of about 1.2 × 10 −15 meters × [atomic mass number] 1 ⁄ 3. Electrons were found to be even smaller.
Models depicting the nucleus and electron energy levels in hydrogen, helium, lithium, and neon atoms. In reality, the diameter of the nucleus is about 100,000 times smaller than the diameter of the atom. Models for an atomic nucleus consisting of protons and neutrons were quickly developed by Werner Heisenberg [63] [64] [65] and others.
After the neutron was discovered, scientists realized the helium nucleus in fact contained two protons and two neutrons. Discovery of the neutron Physicists in the 1920s believed that the atomic nucleus contained protons plus a number of "nuclear electrons" that reduced the overall charge.
The reason is that every time you add a neutron, you’re creating a new nucleus that is going to decay. So, you must add the neutrons fast enough to get all eight neutrons into the target nuclei ...
Hydrogen was known to be the lightest element, and its nuclei presumably the lightest nuclei. Now, because of all these considerations, Rutherford decided that a hydrogen nucleus was possibly a fundamental building block of all nuclei, and also possibly a new fundamental particle as well, since nothing was known to be lighter than that nucleus.