How can two atoms of the same chemical element be different?


A.

They may be different allotropes of the element. Each allotrope of the same element has a different number of neutrons.


B.

They may be different isotopes of the element. Each isotope of the same element has a different number of electrons.


C.

They may be different isotopes of the element. Each isotope of the same element has a different number of neutrons.


D.

They may be different allotropes of the element. Each allotrope of the same element has a different number of electrons.