Halogens Song Periodic Table

The video tutorial introduces the halogens, elements in Group 17 of the periodic table, known for being nonmetallic and salt-forming. It covers each halogen: Fluorine, the lightest, with atomic number 9; Chlorine, a yellow-green gas at room temperature; Bromine, extracted from brine pools; Iodine, occurring in various oxidation states; Astatine, the rarest naturally occurring element; and Tennessine, a recently discovered element expected to belong to the halogen group. The video emphasizes their properties, atomic numbers, and masses, providing a comprehensive understanding of these elements.

What is the significance of the term 'halogen'?

What is unique about Astatine according to the text?