Question

All Isosters are isoelectronic but all isoelectronic species are not Isosters . Explain with example.

Answer 1

Isosters are those atoms which have similar number of electrons in their valence shell. For example F and Cl. They have 7 electrons each in their outermost shell. In fact every group in Mendeleev's period table represent the members of Isosters group. Isosters could be also from different groups. For example F- is isoster with H-.

Isoelectronic species are those atoms/ions having same electron numbers but with different nuclear charges

Answer 2

Isosters are those atoms which have similar number of electrons in their valence shell. For example F and Cl. They have 7 electrons each in their outermost shell. In fact every group in Mendeleev's period table represent the members of Isosters group. Isosters could be also from different groups. For example F- is isoster with H-.

Isoelectronic species are those atoms/ions having same electron numbers but with different nuclear charges.