The question is a little confusing to me but I would answer that they have different number of protons, different number of neutrons, and different number of electrons.
But your question MAY means copper arsenide, germanium arsenide, silicon arsenide etc.
How is the atomic structure of a Copper differ from Germanium, Silicon and Gallium Arsenide ?
Tnx :))
2 answers
The atomic number of copper is 29 and in its outermost shell it has only one electron in other words its outermost shell is incomplet.While atomic number of germanium is 32 ans silicon is 14 their outermost shell has 4 electrons and their outermost shell is complete as they form covalent bond.And galium arsenide is a combination of two elements so it is a compound semo conductor.Both gallium and arsenic shares its outermost electrons.