Boron is an element with the atomic number 5, which means it has 5 protons in its nucleus. The number of electrons in an atom is usually equal to the number of protons, so boron has 5 electrons. As for neutrons, the number can vary depending on the isotope of boron. The most common isotope, boron-11, has 6 neutrons, while the less common isotope boron-10 has 5 neutrons.