Interesting question, with a complicated answer. Toward the surface the material is thought to be a lattice of nuclei (probably iron) with a free flowing sea of electrons interspersed. Further down there may be free neutrons interspersed as well, so the identity of the elements that form the material is confused. At the innermost depths the material is esssentially a mass of neutrons without any differentiation of "atoms," and hence no elemental identity. Strange stuff indeed.