Question

no of neutrons is halved no of electrons doubledwhat is mass of oxygen

Answer 1

no of protons= no of electrons = 8×2=16
no of actual Neutrons= mass no - atomic no
= 16-8=8
(since no of Neutron is halved )
no of Neutrons= 4
mass of O2 = no of protons+no of Neutron
= 16+4=20