Explain how the isotopes of an element differ.
They each have a different number of electrons in their outermost energy level.
They each have a different number of protons in their nuclei.
They each have a different number of neutrons in their nuclei.
They each have a different charge.
They each have a different number of electrons in their outermost energy level.
They each have a different number of protons in their nuclei.
They each have a different number of neutrons in their nuclei.
They each have a different charge.