Location on the Periodic Table
These reactive nonmetals have seven valence electrons. As a group, halogens exhibit highly variable physical properties. Halogens range from solid (I2) to liquid (Br2) to gaseous (F2 and Cl2) at room temperature. The chemical properties are more uniform. The halogens have very high electronegativities. Fluorine has the highest electronegativity of all elements. The halogens are particularly reactive with the alkali metals and alkaline earths, forming stable ionic crystals.
Summary of Common Properties
- Very high electronegativities
- Seven valence electrons (one short of a stable octet)
- Highly reactive, especially with alkali metals and alkaline earths