OPOpenPithMake curiosity visibleCHEMISTRY LAB / 02

The Periodic Table

118 elements, raised by their properties.

Click an element to view its atom · drag to orbit · right-drag or two fingers to pan · scroll to zoom

About Radium

Radium is a chemical element; it has symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather than oxygen) upon exposure to air, forming a black surface layer of radium nitride (Ra3N2). All isotopes of radium are radioactive, the most stable isotope being radium-226 with a half-life of 1,600 years. When radium decays, it emits ionizing radiation as a by-product, which can excite fluorescent chemicals and cause radioluminescence. For this property, it was widely used in self-luminous paints following its discovery. Of the radioactive elements that occur in quantity, radium is considered particularly toxic, and it is carcinogenic due to the radioactivity of both it and its immediate decay product radon as well as its tendency to accumulate in the bones.

The text above is from the lead of the Wikipedia article “Radium” (retrieved 2026-11-05), used under CC BY-SA 4.0. Read on Wikipedia · CC BY-SA 4.0

Data and notes

Column height is a linear display mapping; the shortest column is not zero. Data: PubChem, IAEA.

Solid columns are measured, frosted glass is predicted, empty frames have no value.

1–5 height · [ ] previous/next · Enter atom · S sample · D demo · Esc table · , . cool/heat · T room temperature · L spotlight/full light · Space replay · R reset view