From a study of properties of neighbouring elements, the properties of an unknown element can be predicted - justify with an example.

Explanation

From study of adjacent elements and their compounds, it is possible to predict the characteristics of certain elements. These predictions were found to be very accurate. These predicted properties helped the future scientists in the discovery of unknown elements. e.g : `E_(Ka)` Aluminium (`E_(Ka)` Al) (now known as Gallium): `E_(Ka)` Silicon `(E_(Ka) Si)` (now known as Germanium), `E_(Ka)` Boron `(E_(Ka)B)` (now known as Scandium).
Illustration: Following table shows a comparison of the properties predicted by .Mendeleeff. for the elements and those found experimentally after their discovery.