Which Statement Concerning Atoms Is FALSE

Multiple Choice

Which statement concerning atoms is FALSE?

A) The atomic number of an atom is the number of protons it contains.
B) The mass number of an atom is the sum of the number of protons,neutrons,and electrons it contains.
C) The nucleus of an atom contains its protons and neutrons,and is positively charged.
D) The nucleus of an atom is the heaviest part of the atom.
E) Electrons reside outside the nucleus in what is called the electron cloud.