Questions tagged [isotopes]
198 questions
88
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3 answers
Why can Hiroshima be inhabited when Chernobyl cannot?
There was an atomic bomb dropped in Hiroshima, but today there are residents in Hiroshima. However, in Chernobyl, where there was a nuclear reactor meltdown, there are no residents living today (or very few). What made the difference?
user14154
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5 answers
Why is technetium unstable?
Is there a simple account of why technetium is unstable?
From the Isotopes section of Wikipedia's article on Technetium:
Technetium, with atomic number (denoted Z) 43, is the lowest-numbered element in the periodic table that is exclusively…
Niel de Beaudrap
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46
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4 answers
Is it possible that every single isotope is radioactive, and isotopes which we call stable are actually unstable but have an extremely long half-life?
I've read that tellurium-128 has an half-life of $2.2 \times 10^{24}$ years, much bigger than the age of the universe.
So I've thought that maybe every single isotope of every single atom are radioactive, and isotopes which we call "stable" are…
Quantum Force
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37
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Why do nuclei decay so fast and slow?
Why do nuclei like Oganesson (also known as Ununoctium, this is the 118th element on the periodic table) decay in about 5 milliseconds? This is weird that they decay. In comparison, why do elements like uranium take about 200,000 years to decay, or…
science error
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29
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3 answers
What does it mean when an isotope is stable?
Does stable mean that an isotope has a very long half life, for example xenon-124 has a half life of 1.8 x 10^22 years, or does it mean that fissure is theoretically not possible, or does it mean that the isotope has a very long half life, but the…
inf3rno
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29
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3 answers
Why is caesium-137 more stable than caesium-134?
Caesium-133 is stable. Caesium-134 and cesium-137 are radioactive isotopes of cesium with half-lives of 2.065 years and 30.17 years respectively.
Why does cesium-137 have a longer half-life if it contains three more neutrons than caesium-134 and…
Melanie Shebel
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21
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2 answers
Isotope that decays when ionized
Some time ago, I read about a certain isotope that is stable when neutral but decays with electron emission (beta) when being completely ionized, but I can't find which one it was.
Which isotope decays when fully ionized?
iblue
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21
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2 answers
Is there a known isotope that generates anti-matter?
I heard that even a banana generates a minute quantity of antimatter. Does any know radioactive nuclear reaction produce antimatter along with alpha, beta and gamma radiation?
Dasa
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20
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Why is nitrogen (with 7 protons and 7 neutrons) so much more abundant than any other odd-odd isotope?
Having an even number of neutrons and/or an even number of protons tends to make a nucleus more stable against radioactive decay. There are only 5 stable nuclei with both an odd number of neutrons and an odd number of protons:
hydrogen-2…
John C. Baez
- 765
17
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2 answers
Why is there a sudden drop-off in half-life of isotopes at around 130 neutrons? Is there a name for this?
Pertaining to the chart of nuclides, there is a region above Bismuth, in which the relatively continuous trend of stability is interrupted by a batch of isotopes all with extremely short half-lives. I know that "magic numbers" contribute to the…
Xiphosura
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17
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2 answers
Why do different elements have different number of isotopes?
For example: Carbon-12,Carbon-13 and Carbon-14 are three isotopes of the element carbon with mass numbers 12, 13 and 14 respectively. Lithium-6 and Lithium-7 for lithium,etc.
My question is that are the number of isotopes for an element a random…
Divyanshu
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17
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3 answers
Is a neutron star basically an isotope?
Since a neutron star is basically just a vast amount of densely packed neutrons, I was wondering whether those neutrons form a single "atom" (of atomic number zero) or whether they are further apart and in a QFT-sense isolated?
Tobias Kienzler
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15
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3 answers
Why do the waters of the different oceans of the world have different ratios of their H and O isotopes?
I was reading about the Kelvin, then water, which defines it, so I ended up reading about the VSMOW. It's based on "average" ocean water.
From https://en.wikipedia.org/wiki/Vienna_Standard_Mean_Ocean_Water :
"VSMOW is a recalibration of the original…
15
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3 answers
Why some nuclei with "magic" numbers of neutrons have a half-life less than their neighbor isotopes?
It's easy to find the "magic" numbers of neutrons on the diagrams of alpha-decay energy: 82, 126, 152, 162. Such "magic" nuclei should be more stable than their neighbors.
But why some nuclei with "magic" numbers of neutrons have a half-life…
voix
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14
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Why do heavier isotopes of the same element have smaller atomic radii than lighter isotopes of the same element?
I have been trying to figure out why higher-mass isotopes have higher melting and boiling points than lower-mass isotopes of the same element.
A Quora answer on this topic explored the idea that electron orbits in atoms with smaller nuclei behave…
Tom Brooks
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