thanks hootenanny im not sure if my teacher had set this question wrongly or not? because im finding it hard to answer. the question goes: TWO statement below are INCORRECT. which are these 2 statements? A.) the nucleus of an atom contains only neutrons and protons. B.)The mass number(nucleon number) of an atom = number of protons + number of neutrons. C.)The Nucleus of an atom contains 3 protons and 4 neutrons. Thus, this atom has 3 valence electrons. D.)It is possible for the mass number(nucleon number) and atomic number(proton number) of an atom to be equal. E.)It is never possible for the number of neutrons and the number of protons to be equal. can anybody help? i could only pick out 1 incorrect statement which is C. but the question require 2.. so i hope somebody could help. thanks lotsa.