#9 Fluorine

Fluorine is a chemical element with symbol F and atomic number 9. It is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. As the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.

Atomic mass:18.998404 amu

Melting point:-219.62 C (53.530006 K, -363.31598 F)

Boiling point:-188.14 C (85.01 K, -306.652 F)

Density:293 K: 1.696 g/cm3