Question

An atom of sodium has an atomic mass of 23 and an atomic number of 11. The atom contains...?

23 protons, 23 electrons, and 11 neutrons.

11 protons, 11 electrons, and 12 neutrons.

11 protons, 12 electrons, and 11 neutrons.

23 protons, 12 electrons, and 23 neutrons.

Answer 1

atomic mass = # protons + # of neutrons

in a neutral atom, # of protons = # of electrons