Question

Consider the following elements:
Li, Cl, Br, Na, K, I
(i) Arrange the elements according to the groups to which they belong in the Periodic Table.
(ii) What are the common properties on the basis of which the elements have been grouped together?

Answer 1

(i) Li, Na and K are grouped together in the periodic table and belong to group I. They are grouped together because all of them have one electron in their valence shell. Rest of the elements Cl, Br and I are grouped together in the periodic table and belong to group 17.
(ii) The elements of group 1 are called alkali metals because they react with water to liberate H₂ gas and form alkalis. The elements of group 17 are monovalent non-metals. They from acidic oxides and are called halogens.