If an atom contains 11 protons and 12 neutrons, what is its atomic number?

1 Answer
Sep 7, 2016

#Z," the atomic number"# #=# #11.#

Explanation:

#Z# is specified by the number of nuclear protons; i.e. the number of positively charged nuclear particles. #Z# specifies the identity of the nucleus. If #Z=11#, then the element is sodium. We would thus describe this species as #""^23Na#.