If an atom has the electron configuration 1s22s22p 1 , how many electrons must it gain to achieve an octet?

According  to  octet  rule  element  has  eight  electrons  in  its valence shell.This  give it  the  same  electronic  configuration  as  a  group  18  elements.Atom  with  electronic  configuration  1s2 2s2 2p1  require  five  electrons  to  achieve  octet. This  is  because the  valence  electrons  are  3 in 2s2  and 2p1  and  hence require  5  electrons  to  be  filled.

The correct answer is b