What is the basic particle of an element?
The most fundamental particle of an element is a proton.
The number of protons determines the identity of the element.
The number of electrons is determined by the number of protons. In a neutral element the number of electrons will equal the number of protons.
The number of neutrons can vary between atoms of the same element. The number of neutrons that create a stable nucleus is affected by the number of protons.