How are isotopes of the same element different from one another?

Isotopes of the same chemical element are atoms that share the same atomic number—meaning they have the same number of protons and occupy the same position in the periodic table—but differ in their number of neutrons.123

Because they possess different numbers of neutrons, isotopes of the same element are distinguished by the following characteristics:

• Atomic Mass: They have different atomic masses and mass numbers.123
• Physical Properties: Variations in mass and nuclear structure lead to differences in physical properties, such as density, atomic velocity, and how they emit or absorb light.43
• Nuclear Stability: Differences in the arrangement of protons and neutrons can affect nuclear stability; for example, one isotope of an element may be stable while another is radioactive.4
• Nuclear Spin: Isotopes may have different angular momentum or spin, which influences how they interact with magnetic fields.4

Despite these differences, isotopes of the same element exhibit nearly identical chemical behavior.13