The atomic number of sodium is 11 and its mass number is 23. It has I. 11 neutrons and 12 protons II. 12 protons and 11 electrons III. 11 electrons and 12 neutrons IV. 12 electrons and 11 neutrons
The correct option is C An atom of sodium has 11 protons, 11 electrons, and 12 neutrons. An atom is an uncharged species .It must therefore comprise an equal number of protons and electrons .This number is denoted by atomic number ,by contrast , the mass number tells us the sum of the number of protons and number of neutrons in an atom of a given element.The number of neutrons may not be the same as the number of protons or electrons.
