What is the atomic number of boron $10$?

Hint: We have to know that a chemical element that is represented by a symbol B is boron. We should know that boron is a Group $13$ element and it belongs to period $2$. We should know that boron belongs to p-block and it is seen in black-brown color. We know that the physical state of boron is metalloid.

Complete step by step answer:
We can define the atomic number or proton number of a compound component as the quantity of protons found in the core of each atom of that component. The atomic number remarkably recognizes a chemical component. It is indistinguishable from the charge number of the core. In an uncharged molecule, the atomic number is additionally equivalent to the quantity of electrons.
We can say that the electronic configuration of boron is $\left[ {He} \right]2{s^2}2{p^1}$. The electrons found in per shell of boron are $3$.
We know that the number of protons in Boron is five and the number of electrons in Boron is five. So, we saw that the atomic number is the quantity of proton found in the nucleus. In boron, the nucleus has five protons. So, we can say that the atomic number of boron is five.

Note: We could define mass number of element as the sum of atomic number and quantity of neutrons found in the nucleus. We have to know that the mass number of boron-$10$ is $10$. In the nucleus of boron-$10$, the number of neutrons is $5$ and the number of protons is $5$. So, when we sum up these two, we get the mass number as $10$.