Please help with this science assignment

Can someone me with questions 15 to 17 plz.

The name of the ion, s2-, is: sulfurous ion sulfide ion sulfur ion sulfate ion

Sodium nitrite (nano2) reacted with 2−iodooctane to give a mixture of two constitutionally isomeric compounds of molecular formula c8h17no2 in a combined yield of 88%. draw reasonable structures for these two isomers. click the "draw structure" button to launch the drawing utility. place the two compounds in the appropriate boxes below.