Chemistry Stack Exchange
Chemistry Stack Exchange

Questions tagged [isotope]

This tag should only be applied where the effects are specifically related to variance in mass number with the same atomic number (existence of isotopes). Examples include: radioactivity and other nuclear properties, kinetic effects, specific relevance to spectroscopy (e.g., NMR, IR), isotope separation, isotopic analysis.

An atom (or aggregation of atoms) of a particular element identified by mass number and distinguished by the number of neutrons in its nucleus. Any atom of any given element can be classified as an isotope, so questions should be limited specifically to effects related to variance in mass number. Examples are:

  • Radioactivity and other nuclear properties
  • Kinetic effects
  • Specific relevance to spectroscopy (e.g., NMR, IR)
  • Isotope separation
  • Isotopic analysis
168 questions
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Why atomic masses aren't integers?

Most of the elements have isotopes, so the atomic masses are calculated depending on the percentage of the existing isotopes. That is clear. However, what about elements that have only one isotope (monoisotopic) - like fluorine? Shouldn't the atomic…
waterlemon
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Does hydrogen really have seven isotopes?

I know that there are 3 isotopes of Hydrogen. But according to this website it is showing 7 http://periodictable.com/Properties/A/KnownIsotopes.htmlWebsite
Apurv Zoad
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Is it possible to find the ratio of isotopes only given the mean mass number?

Three isotopes of an element have mass numbers $(M)$, $(M+1)$ and $(M+2)$. If the mean mass number is $(M+0.5)$, then the ratio of the amounts of the three isotopes is? Let amount of $(M)$, $(M+1)$, and $(M+2)$ be $x$, $y$ and $z$…
Abhigyan
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Why is Nitrogen 15 found almost exclusively in marine environments?

Prelude The following story was told to me earlier this summer Every year during October, the Pacific rain creates an ideal spawning condition for the wild Pacific salmon in the coastal forests of British Columbia. Of course, when we think of salmon…
John Snow
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5
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The effects of adding neutrons to an atom

So neutrons are neutral in terms of charge, and adding neutrons to an atom affects its atomic mass. But when neutrons are added to the nucleus, the nuclear radius would be affected. Couldn't that affect how the charge of the nucleus is distributed…
Jean Valjean
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Can carbon dating tell how long a species would survive?

Carbon ($\ce{^{14}C}$) is used to determine how long a particular species has lived or how old it is. Can we use the same isotope to derive how long a species may survive? (My understanding is still quite at infant level on half-life concept) Is it…
bonCodigo
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Protactinium-234 half-life

This is going to seem like a rather daft question, but what is the definitive half-live for protactinium-234 (234Pa)? I'm seeing lots of different answers in various academic papers etc. For instance, in Bonotto & Andrews (2000) the half-life of…
cjms85
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Who figured out that different isotopes have different numbers of neutrons?

I reasearched about the history of the discovery of neutrons and couldn't find who found out that isotopes are a change in the number of neutrons. Can you please tell me who it was that made this discovery?
Amruth Arunkumar
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Why is the standard atomic weight of chlorine not a whole number?

Why is the standard atomic weight of chlorine, 35.5, not a whole number? Like for example, it could be exactly 35 or exactly 36. Please show the solution of formulae on how u reach to 35.5) with some English words so I can write the answer in my…
A Cool Guy
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Obtaining deuterium directly from water

I know that there is 2:6400 deuterium and hydrogen molecules respectively in water. When electrolysis is done, hydrogen and oxygen will be obtained. The hydrogen obtained should contain small amounts of d2 and t2. Is there a way to separate it by…
nihaljp
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Isotopes and their percentage existence in atmosphere

When we talk about percentages of isotopes of an element in the atmosphere, is it percent by mass or volume or weight or something else?
user28386
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Isotope pairs in different states at room temperature?

Does any pair of isotopes exist which are in different states at room temperature—either in isolation or as part of an otherwise-identical compound?
Richard Simões
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Estimating for atomic number for an "unknown element"

A questions tells me there's this element with 3 isotopes (270.51 amu, 34.07% abundance; 271.23 amu, 55.12%; and 269.14 amu, 10.81%), and to solve for average atomic mass. I have done so and got 271 (270.758) for its atomic mass. Then it asks me to…
kira
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Can the word "iso" be used if the quantities are zero in number?

Both $\ce{H+}$ and $\ce{He^2+}$ ions have zero electrons. So can we call them isoelectronic species? And if two species have a difference in the number of protons and neutrons equal to zero, can we call them isodiaphers? Finally, I know that only…
Nipun Kulshreshtha
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How to find the relative abundances of isotopes of an unknown element?

An unknown element $\ce{Q}$ has two unknown isotopes: $\ce{^60Q}$ and $\ce{^63Q}$. If the average atomic mass is $\pu{61.5 u}$, what are the relative percentages of the isotopes?
Teresa
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