Radium

About this element

Symbol: Ra
Date of discovery: 1898
Name origin: Latin radius
Appearance: silvery white metallic
Discoverer: Marie and Pierre Curie
Obtained from: uranium-bearing ores

Melting point: 700 K
Boiling point: 1737 K
Density[kg/m³]: 5.0
Molar volume: 41.09 × 10^-6 m³/mol
Protons/Electrons: 88
Neutrons: 138
Shell structure: 2,8,18,32,18,8,2
Electron configuration: [Rn]7s2
Oxidation state: 2
Crystal structure: cubic

An intensely radioactive element, radium is an alkaline earth metal that is found in trace amounts in uranium ores. Its most stable isotope, ²²⁶Ra, has a half-life of 1,602 years and decays into radon gas. Radium emits alpha, beta, and gamma rays, and when mixed with beryllium produces neutrons. Inhalation, injection, or body exposure to radium can cause cancer and other body disorders. In the early 20th century, radium was used to paint watch dials and hands due to its luminescent qualities. The dial painters, mostly women in their early twenties, were some of the first victims of radioactive poisoning.