[cashsphere]

Do elements with natural occuring isotopes and radioactive isotopes look the same or different? How could you tell what isotope the element is?

[billnotgatez]

density

[limpet chicken]

Reactivity would also be affected, a least in some instances, for example, deuterium, or heavy hydrogen, is slightly less reactive than ordinary hydrogen (protium), and tritium, the radioactive hydrogen isotope, is heavier, and slightly less reactive still.

[jdurg]

Reactivity would also be affected, a least in some instances, for example, deuterium, or heavy hydrogen, is slightly less reactive than ordinary hydrogen (protium), and tritium, the radioactive hydrogen isotope, is heavier, and slightly less reactive still.

This applies to hydrogen, but it may not, and usually does not, apply to heavier elements.  With hydrogen, the addition of a neutron will close to double the mass of the atom, thus affecting how it "moves" around and reacts.  With heavier elements like uranium and lead, the addition of a couple neutrons has almost no effect on the overall mass.  So for the lighter elements, the reactivity may differ a bit.  But for the heavier elements, the difference in reactivity is incredibly small.