# Why is the atomic mass of the sodium atom "23 amu"?

##### 1 Answer
Dec 20, 2017

The atomic mass of sodium is defined by the number of massive nuclear particles....

#### Explanation:

And by DEFINITION, sodium has 11 protons, massive, charged, nuclear particles, the which number defines the element as sodium, i.e. $Z = 11$, and most nuclei contain 12 neutrons, massive neutral, nuclear particles.

And so we gets the isotope ""^23Na....which is 100% abundant to a first approximation....How many electrons does a NEUTRAL sodium atom contain?