Questions tagged [isotopes]

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Are Isomers identical?

I confused that is isomers are identical or not? If yes, how about $^4$He and D$_2$? If not, how about same molecular in different electronic energy level, how about same electronic energy level but ...
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Why $\rm Ag$ 108 decays into $\rm Cd$ 108 most of the time?

In the table of nuclides, it shows that $\rm Ag$ 108 can go through either electron capture or beta- decay (though the branching ratio for electron capture decay is much lower). What determines that? ...
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1 answer
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Examining isotope shift in ions vs neutral atoms - why use ions?

I'm currently deep-diving isotope shift (IS) spectroscopy literature. I've come across several papers that look at the isotope shifts of charged ions, and I want to try and understand why researchers ...
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Does each spectral line of an atom/molecule have a unique lineshape?

A spectral line is determined by a particular transition in an atom or molecule. In reality, this line isn't infinitely sharp, but has a small distribution about the resonance frequency as a result of ...
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How can negative beta-decay energy be negative?

The International Atomic Energy Authority (IAEA)'s Nuclear Data Services list tables of nuclear data, including a table of atomic masses and beta decay energies, data taken from Huang et al., Chin ...
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If there was no weak nuclear force, what would be the heaviest stable theoretically stable isotope with equal protons and neutrons?

If there was no weak nuclear force, what would be the heaviest stable theoretically stable isotope with equal protons and Neutrons? For our universe the heaviest such isotope is calcium 40, but most ...
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Why are fermionic atoms less prevalent than bosonic ones?

Many atoms have no stable fermionic isotopes. Those that do typically have more stable bosonic isotopes than fermionic ones. Furthermore, the fermionic isotopes of most atoms are lower in natural ...
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2 answers
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If plutonium-238 (Pu-238) absorbs a neutron, does it become Pu-239?

I am asking this simple question because I am always hearing about how thorium reactors are less perilous to the world because, unlike uranium reactors, they produce some Pu-238, which is not suitable ...
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What determines the half-life (or stability) of an isotope?

Why is it that some elements do not have any stable isotopes, while others of very similar mass have multiple stable isotopes? What determines this phenomenon and what determines the strict ...
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Hypothetical NMR experiment

Say I set the RF of NMR to resonate to a specific frequency of a specific isotope of nitrogen, based on the magnetic field strength of the NMR machine, Now, imagine if I had put in egg whites(or any ...
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8 votes
3 answers
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How can I determine if an element undergoes electron or positron emission?

I'm not sure how I can determine whether an element has $\beta^-$ or $\beta^+$ emission, or no $\beta$ emission at all. I'm told that positron decay happens when there are too many protons and not ...
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Is there an online resource for fusion outcomes of various elements at various energy levels?

I'm looking to find a chart of nuclides, their potential fusion products and measured energy levels, in a similar vein as NuDat 3, but for fusion. It doesn't need to be cleanly formatted like NuDat, ...
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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 ...
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Number of Spins Up and Down (Neutron and Proton)

I would like to know that if I was given an isotope, can I know the number of up (down) spins for neutron and proton? For example for Ge-73, what steps should I take in order to know the number of ...
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2 answers
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What are the chemical properties of uranium-233 that makes it a more efficient fuel than uranium 235?

i'm trying to find what the best nuclear fuel would be. I've already tried finding this answer online but there's nothing that helps. i would like to find an answer please. btw, by efficient, i mean ...
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Can the Schrödinger equation be solved for deuterium?

Or does the added neutron complicate things too much?
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Does every element have a half-life?

Will every element slowly decay into something else? Or do some isotopes have infinite half-lives?
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Stabilizing an isotopic lattice for information storage

I currently have next to no know-how on quantum or molecular physics so bear with me. The theoretical issue is that as molecules are in perpetual motion and/or have an average kinetic energy across a ...
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1 answer
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Why do different atomic isotopes have different atomic spectrums?

We know that different elements have different atomic spectrums as a result of the difference in charge and electron shielding that occurs when extra protons are added to a nucleus. We also know that ...
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1 answer
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Why are lithium-$7$ and boron-$11$ respectively more abundant than lithium-$6$ and boron-$10$?

Lithium, beryllium and boron are unusually low in abundance for low-$Z$ elements, because their stable isotopes aren't the ones stellar nucleosynthesis makes without consuming them. What little ...
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Question about potential additives to a very relative Covid 19 m R N A patent (i.e. radio active Ions: Iodine 125 or 131, Strontium 89, cesium, etc.) [closed]

I am a genuinely concerned citizen with barely any scientific background concerning radioactive isotopes. However, I have a question about items listed in an mRNA 1273 patent on Moderna's website. ...
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1 answer
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Stable nuclear isotopes

It appears that all stable nuclei may be seen to be composed of pairs of smaller, stable nuclei, e.g., the Li-7 nucleus seemingly is composed of H-3 and He-4, i.e., 1(3) + 2(4) -> 3(7). What if any ...
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What is an "excited nuclear isomer"?

I have been making an excel spreadsheet of all nuclides with half-lifes 20 hours or longer. If you look on the any of Wikipedia's "Isotopes of [insert any found element here]" pages, you ...
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Why is Palladium-108 "theoretically capable of spontaneous fission?"

I was just reading Wikipedia's page on palladium isotopes and I noticed the note about Palladium-108. It says "theoretically capable of spontaneous fission", but I don't find that explained ...
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Extrema in the Table of Nuclides [closed]

Symbolic picture of a nuclid chart: I would like to know for which $Z$ the area in the nuclide map has the greatest width and for which $N$ and the greatest height. Does anyone know? Note: I don't ...
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Why is the number of isotopes of an element bounded?

Is there a known reason why any given element has finitely many isotopes? Here I mean both stable and unstable isotopes. If we know this, do we have a reason why, for a given element, are the isotopes ...
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3 votes
2 answers
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Can muons be used to reach the island of stability of superheavy elements?

While reading about the island of stability of superheavy elements[0], experimental approaches and related difficulties[1], an idea has formed in my head. Since I cannot find considerations of such ...
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3 votes
4 answers
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Conceptual half-life Question

So I have this word problem and I’m a bit confused about it. I have the answer and explanation but I still don’t understand: The half-life of carbon-14 is approximately 5730 years, while the half-life ...
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Can we use tritium instead of helium-3 for nuclear fusion reactors?

I know that tritium isn't entirely stable (half-life of about 12.3 years) and might require a lot of energy to create large amounts (and transport/handle safely), but wouldn't that still be easier (...
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3 votes
3 answers
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What is the exponential (or geometric) rule (or law) for uranium enrichment?

Uranium ore starts at about .72% U-235... At ~20% U-235, it is considered to be about '90% of the way' to weapons-grade uranium, which is about ~90% U-235... Because uranium enrichment in centrifuges ...
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5 votes
2 answers
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Why are nuclides with an even number of protons and neutrons more stable?

I am currently learning about Radioactivity and Nuclear Physics. Why are nuclides with an even number of protons and neutrons more stable? I have read that nuclides with an even number of protons or ...
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Why is helium-3 stable?

Why is helium-3 stable? Besides hydrogen, helium-3 is the only isotope that has a neutron-to-proton ratio less than 1. Why is it not radioactive?
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ISOTOPE.one of the two or more species of ATOMS [closed]

ISOTOPE, One of the two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behaviour but with different atomic ...
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1 answer
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Can Uranium-238 undergo ordinary (single) beta decay?

Can U-238 undergo regular, single beta decay? Are there isotopes which can only undergo double, never single, beta decay? Not even two normal beta decays in quick succession?
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14 votes
2 answers
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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 ...
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4 answers
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What is the '-235' in this question? [closed]

I am self-studying higher level physics currently, and stumbled upon this question: $1 mg$ of uranium - $235$ is completely destroyed in an atomic bomb. How much energy is liberated? I do not ...
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3 answers
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Why arent'the best neutron absorbers always the ones with the largest cross sections? Does the reaction product have something to do with it?

There used to be a question (and answer) here that mentioned why isotopes of cadmium, xenon, hafnium, etc. that have larger cross-sections than boron-10 weren't as good at being neutron absorbers in ...
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2 votes
2 answers
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Why do all living beings absorb the same proportion of carbon 14?

I understand that all living beings have the same proportion of carbon 12 to carbon 14 and that this is an assumption used to carry out carbon dating but I do not understand how this is possible. As ...
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Why is the isotope Nitrogen-14 formed preferentially to Nitrogen-15 in the CNO-cycle in stars?

Most of the universe's nitrogen is formed in larger, main sequence stars using the CNO Cycle, right? But I cannot find a good, specific explanation as to why $^{14}$N, with both an odd number of ...
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2 votes
1 answer
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Why is uranium's atomic weight listed as 238.02891, higher than almost all known isotopes?

The vast majority of uranium is U-238, and most of the rest is U-235, U-232, U-234, etc.... So how can the averaged atomic weight be a little over 238?
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Can the ratio of gravitational force to Coulomb repulsion force in the nucleus be increased by adding neutrons? How many?

As you know, the ratio of gravitational force to Coulomb repulsion force between two protons is very small. This means that the source of nuclear stability cannot be the force of gravity. Can some ...
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Can Uranium-235 absorb neutrons and become U-238 instead of splitting?

Does that happen, on occasion? Does anyone know? I suppose it is quite rare, ... To absorb three neutrons without once fissioning... Could U-235 absorb three neutrons at once? Or just one, becoming ...
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Would Cherenkov radiation be observed in Uranium glass?

I recently read about Cherenkov Radiation and the neat blue glow it creates in underwater nuclear reactors, and my understanding of it is that it occurs due to particles ($\beta$ particles in the case ...
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Why are atomic mass and mass number approximately the same?

I understand that mass number and atomic mass are different by definition.Mass number is the total number of nucleons and isotopic atomic mass is the average atomic weight of all the known isotopes of ...
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28 votes
3 answers
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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 ...
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Mass of Isotope

I am designing a simple Mass Spectrometer. I need to find radius of $Pb_{204}^{-}$ when deflecting. I have this equation: I know everything in that equation except the mass. I have How can I find ...
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Activity of a radioisotope after an hour of irradiaton

Suppose that you irradiate a beam of monoenergetic alpha particles on a target. You can determine the saturation activity using Saturation activity = $\frac{R_a x \sigma \rho N_A}{A}$ But how do you ...
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Half-life vs mean lifeitme. Book error?

This text is from an scholar book (to editors: please, keep original and translated text): La vida mitjana d'un isotop es de 50 anys. Calcula el temps necessari perque l'activitat es reduexi al ...
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1 answer
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What is the $^{28}{\rm Si(}d,p)$ nuclear reaction?

I am reading about several processes in nuclear physics that put letters in parentheses next to the names of the isotopes. Usually two letters, separated by a comma. Besides $d$ and $p$, I have ...
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Lithium Proton Fission [closed]

What will happen if I fire a proton beam at a Lithium-6 nucleus? What products will it produce? Is it exothermic and if so, how much energy is released? How would you calculate it?
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