You might have observed in CO2 molecule, that there are two pairs of valence electrons on each of the oxygen atoms that are not bonded. Such a pair of electrons is called a lone pair. Now how many lone pairs are present is S8 molecule?
16
The structure for S8 molecule is crown shaped. Each sulphur is bonded to 2 other sulphur atoms. The number of valence electrons in a sulphur atom is 6, out of which two are used in bonding with other sulphur atoms. Hence, each sulphur atom is left with 2 lone pairs. For 8 sulphur atoms, there are 16 lone pairs.