Radium is an alkaline earth metal that is found in trace amounts in uranium ores. Radium, in the form of radium chloride, was discovered by Marie Sklodowska-Curie and Pierre Curie in 1898. It was isolated in its metallic state by Curie and André-Louis Debierne through the electrolysis of radium chloride in 1910. Some of the few practical uses of radium are derived from its radioactive properties. More recently discovered radioisotopes, such as 60Co and 137Cs, are replacing radium in even these limited uses because several of these isotopes are more powerful emitters, safer to handle, and available in more concentrated form. It exhibits luminescence, as do its salts. Radium imparts a carmine red color to a flame. Radium emits α, β, and γ rays and when mixed with beryllium produces neutrons.
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Chemical Properties
| Appearance | Silvery White Metallic Solid |
| Atomic Number | 88 |
| Atomic Weight | 226 g/mol |
| Block | s |
| Boiling Point | 1737 °C |
| CAS Number | 7440-14-4 |
| Crystal Structure | Body-Centered Cubic |
| Density | 5.5 g/cm3 |
| EINECS Number | 231-122-4 |
| Electron Configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s2 4d10 5p64f14 5d10 6s2 6p6 7s2 |
| Group | 2 |
| Ionization Energy | 509.3 KJ/mol |
| Melting Point | 700 °C |
| Oxidation State | 2 |
| Period | 7 |
| Symbol | Ra |
