S²⁻ cannot be reduced further.
Explanation:
S²⁻ cannot be reduced further
In the periodic table, Sulphur has the atomic number of 16.
So, the arrangement of electrons in the orbits would be 2, 8, 6
The outermost orbit has 6 electrons.
It can gain two more electrons to complete its outermost orbit and the valency of the sulphur then becomes 2-
Therefore, in S²⁻ the valence electrons are complete in the outermost orbit and cannot gain more electrons. Therefore, it cannot get reduced further.