Answer:
as no. of protons is equals to the no. of electrons so, it is a neutral atom.
but, as Atomic No. = Mass No. - No. of neutrons
Atomic No. = No. of protons = 18
so, Mass No. = Atomic No. + No. of Neutrons= 18 + 20 = 38
so, correct option is C.
Explanation:
