So an atom is made of Electrons, Neutrons and Protons. A atom with 5 Protons MUST have exactly 5 Electrons!!!! Electrons have to cancel out the protons! Unless the atom is called an ‘isotope’ then everything must have the same number as protons as it does electrons. Protons are positively charged while Electrons are negatively charged. The number of protons and electrons also match the Atomic number of an atom also! So in your case this atom is Boron, because it has 5 protons which means it has 5 electrons and it’s atomic number is 5!
Hope this made sense!