the electronic configuration of sulfur is
1s2 2s2 2p6 3s2 3p4
p subshell consists of three orbitals px , py and pz
among them in sulfur for 3P4
px consists two electrons so which is paired
but py and pz consists of single electrons
so sulfur consists of 2 unpaired electrons
you can read Quantum number, Afbau principle and Hund's rule for more idea