What is inert pair effect? Plz explain me briefly .
The tendency of electrons of outermost shell of atom with high atomic number to be unionized (does not involve in chemical reactions) is called inert pair effect.
In general this tendency has shown by elements in and after 4th period of the modern periodic table.
Ex:
(1) Carbon shows valence of ‘4’ and forms stable compounds but tin (Sn) element of the same group forms stable compounds with valence ‘2’ than with valence ‘4’.
(2) Aluminum forms stable compounds by losing 3 electrons to form stable compounds in +3 oxidation state but Thallium (Tl) of same group element prefers to lose one electrons and forms compounds in +1 oxidation state.