64th B.P.S.C. (Pre) 2018
Which of the following elements does not contain neutrons?
aOxygen
bNitrogen
cHydrogen✓ Correct
dNone of the above/More than one of the above
eCopper
Explanation
Hydrogen has atomic number 1. The common isotope of hydrogen (protium) has no neutron. The heavy hydrogen isotope (deuterium) has 1 neutron, while the very heavy hydrogen isotope (tritium) has 2 neutrons.
general-science