In isotope sodium-25, what are the atomic number, number of protons, electrons, and neutrons?

11 protons, 11 electrons, 14 neutrons

Explanation:

Na has atomic number Z = 11, so it has 11 protons (p).

In a neutral atom, the number of protons equals the number of electrons, so there are 11 electrons.

The mass number A =the number of protons plus neutrons = p + n

So, to get the number of neutrons, you take

A – Z = (p + n) – p = n

In words, number of protons = mass number – atomic number

Number = 25 – 11 = 14 .