The sodium atom contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium?
The mass number is the sum of the neutrons and protons in an atom.
So 11 protons + 12 neutrons= 23
We have the
A sneakier question would have asked:
The sum of neutrons and protons, the massive nuclear particles, gives the mass number, with which we often label the elemental symbol as a left hand superscript. But the number of
It is not too difficult to incorporate these ideas into your understanding, and if you have a Periodic Table in front of you (and you should have one NOW!) these problems are straightforward.