Question

How do Group $7$ elements react?

Answer 1

The reactivity of group $7$:

Group $7$elements are known as halogens, they include Fluorine, Chlorine, Bromine, Iodine and Astatine. They are diatomic molecules with electronic configuration ${\mathrm{ns}}^2{\mathrm{np}}^5$.The reactivity of group $7$ decreases down the group.

1. Reaction with Water- This reaction is based on reduction potential. Fluorine and Chlorine has high reduction potential . Thus, Fluorine and chl react with water but due to low reduction potential other halogens do not react with water . $2{\mathrm{F}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)\to 4\mathrm{HF}\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right),3{\mathrm{F}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)\to 6\mathrm{HF}\left(\mathrm{g}\right)+{\mathrm{O}}_3\left(\mathrm{g}\right)$
2. Reaction with Hydrogen- The bond strength is very weak down the group. All the halogens form covalent bond with hydrogen as$HF>HCl>HBr>HI$ . All the hydrogen halides are soluble in water and produces strong acids.$\mathrm{HX}+{\mathrm{H}}_2\mathrm{O}\to {\mathrm{H}}_3{\mathrm{O}}^{+}+{\mathrm{X}}^{-}\left(\mathrm{g}\right)$
3. Group 1: The Alkali Metals- All the halides react alkali metals to produce salt.$2\mathrm{Na}\left(\mathrm{s}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to 2\mathrm{NaCl}\left(\mathrm{s}\right)$.
4. Group 2: The Alkaline Earth Metals- All the halides react with alkali earth metals to produce hydrated halides.$\mathrm{M}+{\mathrm{X}}_2\to {\mathrm{MX}}_2$

Thus, The reactivity of group $7$decreases on moving down the group.