Editing Chemical element (section)

=== Atomic numbers ===
The known elements have atomic numbers from 1 to 118, conventionally presented as [[Arabic numerals]]. Since the elements can be uniquely sequenced by atomic number, conventionally from lowest to highest (as in a periodic table), sets of elements are sometimes specified by such notation as "through", "beyond", or "from ... through", as in "through iron", "beyond uranium", or "from lanthanum through lutetium". The terms "light" and "heavy" are sometimes also used informally to indicate relative atomic numbers (not densities), as in "lighter than carbon" or "heavier than lead", though the atomic masses of the elements (their atomic weights or atomic masses) do not always increase [[monotonic function|monotonically]] with their atomic numbers.