👉 Radium is a chemical element with the symbol Ra and atomic number 82. It is the lightest known element, with an atomic mass of approximately 79.943 u (atomic units). Radium has various uses in medicine and science, including as a diagnostic agent for cancerous tumors and as a source of radiation for medical research. In terms of radium's role in chemistry, it is used to make radon gas, which is toxic but useful for shielding rad
