An atom of Sodium has 11 protons and a mass number of 13. How many neutrons does it have?

1 Answer
Jan 11, 2016

It would have 2 neutrons. This isotope would be extremely unlikely, and if not extremely short-lived.


The mass number is the sum of the massive nuclear particles, the protons and the neutrons. This source relates that the lightest sodium isotope is #""^18Na#. You might find #""^13Na# as an extremely short-lived isotope in a nuclear reactor - it would undoubtedly be screaming hot.