ASTR 101 Lecture Notes - Lecture 25: Radon, Acute Radiation Syndrome, Radium
5 Sep 2016
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One implication: atoms can be crushed down to much denser states hence neutron stars, a trillion times as dense as water. Two important players in the nuclei of atoms: neutrons (neutral) and protons (positively charged) The neutrons and protons are just about equally massive (and about 2000x as heavy as the distributed electrons). The actual structure is more complex than that, and involves quarks that make up the neutrons and protons. Atomic number = z = number of protons in the nucleus. Z determines the number of surrounding electrons, and thus how it bonds chemically with other elements. Atomic number z does not tell whole story. Nuclei can also contain neutrons. (the mass of the neutron ~ the mass of the proton) Number of protons + number of electrons = atomic mass number. Nuclei that differ in the number of neutrons = isotopes of one another because adding neutrons changes the mass but not the fundamental type of atom.
