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List of Elements of the Periodic Table - Sorted by Atomic Number (516 words) |
 | Atomic number: The number of protons in an atom. |
 | Atomic mass: The mass of an atom is primarily determined by the number of protons and neutrons in its nucleus. |
 | Isotope of an element is defined by the sum of the number of protons and neutrons in its nucleus. |
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List of elements by atomic number - Wikipedia, the free encyclopedia (333 words) |
 | This is a list of chemical elements, sorted by atomic number and color coded according to type of element. |
 | [209], indicates the mass number of the longest-lived isotope of the element. |
 | Atomic weights of elements with atomic numbers from 1-109 taken from this source. |