What is the electron configuration for #S^(2-)# ion?
In your case, the neutral atom is sulfur,
The electron configuration of a neutral sulfur atom will thus be
#"S: " 1s^2 2s^2 2p^6 3s^2 3p^4#
Now, the sulfide anion,
As you can see in the configuration of the neutral atom, these two electrons will be added to the 3p-orbitals, which can hold a maximum of six electrons between them.
The electron configuration of the sulfide anion will thus be
#"S"^(2-):color(white)(a) 1s^2 2s^2 2p^6 3s^2 3p^6#
The noble gas shorthand notation for the sulfide anion will use the electron configuration of neon, the noble gas that comes immediately before sulfur in the periodic table.
#"S"^(2-): color(white)(a)["Ne"] 3s^2 3p^6#