Data sources & scientific notes
Names and electron configurations: PubChem. Isotope choices and natural abundances: NIST Atomic Weights and Isotopic Compositions. Lawrencium’s 7p ground-state configuration follows NIST. Aluminium and caesium use IUPAC spellings; American spellings also work in search. Category boundaries are conventional; superheavy-element categories are nominal. Configurations for elements 104–118 are shown as theoretical. Isotope choices are a reference subset, not a complete nuclide chart. The most abundant listed isotope is selected where abundance data are available; otherwise a listed example is selected, with no claim that it is the longest-lived. Property values also use the PubChem reference table. Radius means van der Waals radius. Electron affinity uses the energy-released convention (positive means favorable electron attachment), opposite in sign to the energy change of attachment. Temperatures are in kelvin; density is in g/cm³. Phase, pressure, allotrope, and measurement conditions can affect physical values; these are reference values, not guaranteed measurements under identical conditions. PubChem may include estimated values. Atomic mass for elements without a standard atomic weight describes a representative isotope and is not necessarily the isotope selected in this app. Reference data retrieved October 26, 2026.