The group 17 elements include Fluorine(F), Chlorine (Cl), Bromine(Br), Iodine(I), and Astatine(At) from the top to the bottom. They are called “halogens” because they give salts when they react with metals.
Halogens are nonmetals, they are very reactive, and the reactivity decreases from fluorine to astatine.
Halogens do not exist in elemental form in nature.
Physical properties of Halogens:
Halogens have a strong and often nasty smell.
They are extremely toxic because of higher electronegativities and effective nuclear charge. These elements also include nonmetallic nature as well as they are radioactive.
Halogens are poor conductors of electricity and heat because they are nonmetallic in nature so they do not have free electrons to conduct heat and electricity
They have low melting and boiling point due to the presence of weak van der walls forces of attraction
Chemical properties of Halogens:
Halogens have seven valence electrons, therefore, they form negative ions and are highly reactive.
Halogens have weak intermolecular forces which are the dispersion forces.
The dispersion forces are progressively weaker for bromine, chlorine, and fluorine.
Molecules of all halogens are homonuclear diatomic i.e molecules exist with two atoms each.
They can gain an electron by reacting with atoms of other elements.
Halogens in the periodic table belonging to group 17 are shown here:
