r15h4bh
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Referring to isotopes of an element
I was watching some Chemistry videos and they often say how there are three isotopes of so-and-so element. When you're referring to the number of
isotopes an element has, does that number include all the possible forms of the element, or do you take the most common form as the normal form and
call the rest isotopes? For example for Hydrogen there are three forms, 1H, 2H and 3H so do you say there are three
isotopes of Hydrogen or do you say that it has two isotopes with 1H being the normal form so it isn't counted as an isotope?
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neptunium
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generally speaking an element is usually refered to as its stable or most common isotope. if another isotope is being used then it is specifically
identify in the litterature.
for example the fusion of deuterium which is the heavy stable isotope of Hydrogen..
or boron 10 is being used to absorbe and slow neutrons not the common Boron..
or U235 undergo fission while the U238 becomes Np239 and Pu239 after absorbtion and transmutation...
does that answer your question?
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Lambda-Eyde
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Quote: Originally posted by r15h4bh  | | For example for Hydrogen there are three forms, 1H, 2H and 3H so do you say there are three isotopes of Hydrogen or
do you say that it has two isotopes with 1H being the normal form so it isn't counted as an isotope? |
No, 1H is also an isotope of hydrogen, so hydrogen has in total three isotopes (if you only count those that can exist within reasonable
timeframes). I see where you're coming from; the usage of the word "isotope" often gives rise to such confusion...
At best, this depends on context. When we chemists refer to chlorine, we refer to a mixture of rougly 75.77 % 35Cl and 24.23 %
37Cl because this is the proportion of which these two isotopes occur in nature and make up the chlorines we use in chemistry. That is
because we're mostly interested in the amount of protons (which define the element) rather than the number of neutrons (except in few cases). In cases
where you're interested in the neutron number in additon to the proton number, you always mention the total mass number in order to avoid confusion.
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neptunium
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which is what i was trying to explain
thank you for articulating it in a much broken down way
when we talk about chlorine we are indeed talking about a mixture4 of the 2 most commonly found isotopes. unless we are conducting an experiment that
only involves such or such isotope in which case it is specified at the begining of the experiment...
thank you Lambda for clearing that out..
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r15h4bh
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Yes, thanks a lot. I was asking whether the more common form is also called an isotope of the element and I checked on wiki and it says there are
three isotopes of H, including 1H. I was just wondering whether 1H was considered as an isotope or not, and it is. Thanks for
clearing that up.  I also got how when you say so-and-so element, you're
generally referring to the most common isotope or isotopes in the case of Chlorine. What I said is correct, right?
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neptunium
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yes you got it !
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