Se stands for Selenium, which is a chemical element with the atomic number 34. Selenium is a non-metal, and it is part of the chalcogen group in the periodic table, which includes oxygen, sulfur, tellurium, and polonium.
Selenium is essential for life in small amounts, as it plays a crucial role in metabolism and helps protect cells from damage. It can be found in various forms and exists as a gray metallic solid or as a red powder. In nature, selenium is typically found in compounds, and it is used in various applications, including photocopiers, solar cells, and as a dietary supplement.