Classification and Appearance
Radium (Ra) is an alkaline earth metal, belonging to Group 2 of the periodic table. This classification signifies its metallic nature, sharing properties with other elements in this group such as calcium and barium.
Color and Luster
When freshly prepared and pure, radium exhibits a lustrous, silvery-white appearance, characteristic of many metals. However, this pristine state is short-lived. Upon exposure to air, the surface of radium rapidly tarnishes, turning black due to its reaction with atmospheric nitrogen to form radium nitride. This rapid tarnishing obscures its initial bright metallic luster.
Texture and State at Room Temperature
Radium exists as a solid at standard room temperature (approximately 20-25 °C). Its texture is typically metallic, though direct handling is not advisable due to its intense radioactivity.
Thermal Properties
Radium, like other metals, has specific melting and boiling points that define its phase transitions.
Melting Point
Radium transitions from a solid to a liquid state at a temperature of approximately 700 °C. This temperature is relatively high for an alkaline earth metal, demonstrating strong metallic bonding within its crystal lattice.
Boiling Point
The boiling point of radium, where it converts from a liquid to a gaseous state, is approximately 1737 °C. This high boiling point further indicates the significant energy required to overcome the interatomic forces present in the liquid phase of the element.