What is the atomic number of boron $$10$$?
$$5$$.
Explanation:
Boron has $$5$$ protons, $$5$$ neutrons and $$5$$ electrons.
The atomic number (also known as the proton number) of Boron is $$5$$ as it has $$5$$ protons.
It has a mass number of $$10$$, as protons and neutron have a relative atomic mass of $$1$$ each, and a neutral charge, as there are equal numbers of $$+1$$ protons and $$−1$$ electrons.