three unpaired electrons Click to see full answer. Herein, how many unpaired electrons are present in as?1 Answer. There are three unpaired electrons.Similarly, how many electrons does an atom of sulfur have in its valence shell? 6 Also, what is the number of valence electrons in phosphorus? five What does unpaired electrons mean?In chemistry, an unpaired electron is an electron that occupies an orbital of an atom singly, rather than as part of an electron pair. Each atomic orbital of an atom (specified by the three quantum numbers n, l and m) has a capacity to contain two electrons (electron pair) with opposite spins.