1. Elements in Group 16 of the periodic table (oxygen, sulfur, selenium, tellurium, and polonium) that form compounds by gaining two electrons.
Usage: chemistry; plural form; singular is 'chalcogen'; also called 'pnictogens' in older usage, though that term now refers to Group 15

Examples

• Oxygen and sulfur are the most common chalcogens found in organic compounds.
• The chalcogens are highly electronegative and readily form anions.
• Selenium is a chalcogen used in photocells and semiconductors.
• Chalcogens typically have six valence electrons in their outer shell.
• The reactivity of chalcogens decreases as you move down Group 16 of the periodic table.