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Why are some nuclei unstable? [closed]

I have a question about unstable nuclei. Someone could explain to me why after 82 protons, nuclei are unstable? And then, what determines the type of radiation they emit?
Santiago Celis's user avatar
1 vote
1 answer
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What is the standard reference medium in which positron ranges data are obtained in property tables, specifically for isotopes used in PET?

What is the standard reference medium in which positron ranges data are obtained in property tables, specifically for isotopes used in (Positron Emission Tomography (PET)? I can't find any valuable ...
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Flux pinning upon a ultracold vapor of neutral atoms

Suppose I have a mixture of two different atoms A and B, both with an even but different number of electrons which fully fill both of their outermost shells. The two are different elements. Now, ...
Young Jun Lee's user avatar
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1 answer
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Ultracold magnetic traps for uranium enrichment

As noted by Mr. Gremlin in this post: How is it possible to accelerate a neutron? Crudely paraphrasing, subatomic particles with non-zero magnetic dipole moments interact with magnetic fields to give ...
Young Jun Lee's user avatar
3 votes
2 answers
459 views

Why does critical mass for radioactive isotopes seem to have little relation to half-life?

I understand that too short a half-life and flash point, becomes kind of meaningless, if the element generates too much heat, so this only applies to longer half-lives. Also, as I understand it, flash ...
userLTK's user avatar
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2 votes
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What is known about the isotope distribution of neutronium decay?

Sometimes it is known to happen. For example, neutron star mergers might result in unstable neutronium droplets which lose the enormous pressure that makes them stable. A "nucleon" of $10^{...
peterh's user avatar
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Changing element and isotope ratio ratio in material in space

Suppose we have a satellite orbiting Earth with a component made of 6061 aluminium alloy. Would cosmic radiation cause the element and isotope ratio of the component to change in a clearly measurable ...
Lars Lau Raket's user avatar
8 votes
1 answer
641 views

Cobalt atomic mass less than 100 % isotope mass? [closed]

Why is cobalt's atomic mass listed on periodic tables as less than 59 amu when its main isotope (virtually 100 %) is cobalt 59 with a trace of cobalt 60? After reading a bit I'm wondering if it has to ...
AZ273026's user avatar
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10 votes
1 answer
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Does antimatter have the same half-life as ordinary matter?

Antimatter is just ordinary matter but with opposite electric charge. Scientists have created only a handful of antihelium-4 in the LHC. I am wondering if the half-life of, say, antiRadium-226 is ...
user6760's user avatar
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2 votes
0 answers
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Most stable isobar for even-$A$ nuclei

In the Liquid Drop Model of the nucleus, the most stable isobar is the one whose atomic number $Z_{A}$ is the one corresponding to the minimum mass, and can be found from the mass parabola or, by ...
Momo's user avatar
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7 votes
1 answer
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Isotopes and electron transitions

Do neutrons in the nucleus (isotopes) affect the frequency of electron transitions through valence shells?
ClancyJohn's user avatar
3 votes
2 answers
375 views

Understanding the decay of Na-22

When looking at data for Na-22 decay (e.g. here: https://www.nndc.bnl.gov/nudat3/DecayRadiationServlet?nuc=22Na&unc=NDS ) it shows that for every 100 decays, there should be: 99.94 gammas with ...
ProgrammingMachine5000's user avatar
1 vote
0 answers
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Finding exhaustive list of isotopes known to have the induced-fission property [closed]

Not sure if this is the right place to ask, since I am looking for help finding information. I am making course material in low level nuclear physics. For this, I've created my own visual Segre Chart (...
nammerkage's user avatar
3 votes
0 answers
70 views

U-235 percentage in nature

It is mentioned everywhere that the percentage of Uranium 235 isotope found in natural uranium is 0.711%. Samples collected from ores around the earth also seem to attest to this claim. Is U-235 0.711 ...
Johnsmith's user avatar
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2 votes
0 answers
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Capillary action for isotope separation

Take, for example, D2O and H2O. As they have different densities, they should have a different maximum capillary height h, where h is defined according to Jurin's law. Then, each isotope of D and H ...
Young Jun Lee's user avatar
1 vote
0 answers
129 views

How the $N/Z$ ratio affects the stability of isotopes and their method of radioactive decay?

Although there is a graph that tells us the number of isotopes and which ones are stable or abundant in nature, like the one below, I have come across the $N/Z$ ratio, which is the number of neutrons ...
Newton's cat's user avatar
1 vote
0 answers
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Water molecule formed by at least one tritium atom

If a water molecule is made up of at least one tritium atom, when the tritium atom(s) decay radioactively, what happens to that water molecule? Does it bond to one or two Helium atoms? Is there any ...
Time Step's user avatar
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If I sent a sample of U238 to the upper atmosphere

If I sent a sample of U238 to the upper atmosphere, would the solar gamma rays be sufficient enough to cause photodisintegration and the subsequent production of Np237?
Young Jun Lee's user avatar
2 votes
1 answer
125 views

What is the half-life of deuterium if protons decay?

If we where to assume that protons decay and we know the half-life of protons, would it be possible to determine the half-life of deuterium? If $^{1}$H (a single proton) has a half-life of, say, $10^{...
Quinali Solaji's user avatar
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0 answers
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Are their pairs of Nuclear Isobars that differ in energy by less then the Lighter Nuclides Characteristic X-ray?

Isobars are atoms (nuclides) of different chemical elements that have the same number of nucleons. According to the https://en.wikipedia.org/wiki/Mattauch_isobar_rule if you have two adjacent elements ...
blademan9999's user avatar
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Potential yields of Np-237 using a synchotron

U238 releases a neutron when it is exposed to photons of around 11 MeV, and the resulting U237 promptly decays into the fissile Np237. In such a situation, what equations can I use to relate the ...
Young Jun Lee's user avatar
1 vote
1 answer
144 views

Is there a way to determine whether a given nucleus is radioactive?

When a nucleus decays it is finding a more stable configuration, as all nature is. But is there a way of finding whether a specific configuration will decay? I know that there is a specific proton-to-...
Saksham's user avatar
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-4 votes
2 answers
368 views

Can moscovium-299 exist and is it possible to predict how stable it will be? [closed]

Five isotopes of element 115 (moscovium) have been created in the laboratory with atomic weights ranging from 286 to 290, each having a progressively longer half-life, ranging from 20ms to 650ms: ...
Larry's user avatar
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1 answer
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Why is U-238 detrimental for nuclear bomb?

I know U-238 is more stable than U-235, because it is an even-even nucleus. Only neutron with energy larger than 1.6Mev can split an U-238, while any neutron can split U-235. But why is the presence ...
poisson's user avatar
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Are very stable super-heavy elements theoretically possible?

I was recently reading about superheavy elements. According to that article all superheavy elements currently known have only been synthesized in laboratory experiments and have a very short half-life,...
LorenzoDonati4Ukraine-OnStrike's user avatar
0 votes
1 answer
62 views

How much $\rm D_2O$ is in Earth's icepacks? [closed]

How much $\rm D_2O$, by mass and/or percentage, is locked in Earth's polar icepacks? Is the $\rm D_2O$:$\rm H_2O$ ratio the same as elsewhere?
RoUS's user avatar
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1 vote
1 answer
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Salt $\rm NaCl$ at the epicenter of a nuclear explosion [closed]

As is known, in the case of neutron irradiation, sodium is converted into the unstable isotope Na-24. This isotope is terribly radioactive. And in the event of a nuclear strike on a salt mine or ...
Jack's user avatar
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7 votes
2 answers
445 views

Why is the deuterium bottleneck temperature 0.1 MeV?

During big bang nucleosynthesis (BBN), deuterium has a lower binding energy per nucleon (~1.1 MeV) than the other similar nuclei, and so prevents heavy elements from forming until the temperature ...
arow257's user avatar
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8 votes
4 answers
2k views

Non-irradiative methods to create radioactive isotopes?

My understanding is that the primary methods with which one can create a radioactive isotope are 1) just waiting for the isotope you want (by means of nuclear decay), or 2) some kind of induced ...
DataScienceNovice's user avatar
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If there wasn't a 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 ...
blademan9999's user avatar
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1 vote
1 answer
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Why is Astatine-210 (At-210) the longest-lived isotope of astatine despite possessing an odd number of neutrons?

I am guessing that isotopes with an even number of neutrons more readily release an alpha particle... When and if At-210 does that, it still has the problem of being 'odd/odd'... But this begs the ...
Kurt Hikes's user avatar
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2 votes
2 answers
89 views

Which proportions of deuterium and tritium did the National Ignition Facility's hohlraum contain?

The National Ignition fusion recently announced the achievement of nuclear fusion "ignition", i.e. more energy released from a sample undergoing nuclear fusion reactions than was directly ...
tparker's user avatar
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1 vote
0 answers
33 views

Why do magic number nuclei have higher first excitation energies?

I have read online that one property of stable 'magic number' nuclei is that they have higher first excitation energies. Why is this?
Elowen's user avatar
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1 vote
1 answer
97 views

Why does the doubly-magic nucleus tin-$132$ have such a short mean lifetime?

Why does the doubly-magic nucleus tin-$132$ have such a short mean lifetime? Only because it is far from valley of stability?
tbb's user avatar
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0 answers
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Does a charged isotope have a different half life than the neutral counterpart?

Let's say you have a radioactive isotope of an element with relatively short half-life (e.g. <0.5s). If you add or remove electrons from the atom so that is has a positive or negative charge, is ...
MFerguson's user avatar
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4 votes
0 answers
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Could there be undiscovered long-lived isomers of unstable elements? [duplicate]

There are 80 stable elements in the periodic table. These elements have at least one stable isotope. Other elements don’t have any identified stable isotopes. The existence of stable isotopes can be ...
哲煜黄's user avatar
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2 votes
2 answers
258 views

Why isn't lead-207 radioactive?

I've recently learnt from here, in an atom, the stability of an atom is described in two contexts, one according to the ratio of neutron and proton of the atom. The ratio will always be between 1 and ...
Projesh Datta's user avatar
4 votes
1 answer
156 views

Why is $^{58}\rm Ni$ the most common isotope or nuclide of nickel if $^{62}\rm Ni$ has the most binding energy (per nucleon) of ANY known nucleus?

Nickel-58 and nickel-62 are four neutrons apart, not even just two, so this fact is especially confusing to me... I have read about how nickel is synthesized in stars from silicon, so this is perhaps ...
Kurt Hikes's user avatar
  • 4,509
14 votes
1 answer
340 views

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 ...
Xiphosura's user avatar
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8 votes
1 answer
1k views

In the event of a disaster at any nuclear power plant other than Chernobyl, would we be dealing with the emission of radioactive iodine isotopes?

Would any nuclear catastrophe emit radioactive iodine isotopes? Do some power plants have different cores that would emit other radioactive isotopes but not iodine isotopes?
bridgemnc's user avatar
  • 183
2 votes
2 answers
209 views

Why does a tritium nucleus have a higher mass than $^3\rm He$?

$^3\rm He$ has a lower (nuclear) mass than tritium which is why the latter decays into the former. This is not explained by the semi-empirical mass formula, which would predict a lower binding energy (...
0x539's user avatar
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General Half-life calculation for an abitrary nucleus

I have been getting back into physics and I was wondering whether there was a generalized half-life equation for any given nucleus composition. For instance for gold isotope 210-AU. Is it possible to ...
Anton von huenerbein's user avatar
1 vote
0 answers
37 views

Would isotopes of hydrogen separate in liquid phase?

According to https://www.aqua-calc.com/calculate/volume-to-weight the difference in density of deuterium/hydrogen in liquid state is 70miligrams/cm^3 vs 169miligrams/cm^3. Would this be a sufficient ...
jhylands's user avatar
1 vote
0 answers
41 views

Easy question regarding RF and ion traps

I saw this interesting video: https://www.youtube.com/watch?v=d-qTa_7FtAA In this video, from the 8:55 mark to 11:55, this man explains using unique frequencies for each element(?) with a unique m/z ...
Young Jun Lee's user avatar
0 votes
1 answer
47 views

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? ...
Anonymous's user avatar
1 vote
1 answer
48 views

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 ...
compp's user avatar
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8 votes
1 answer
573 views

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 ...
compp's user avatar
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0 votes
2 answers
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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 ...
GMSL's user avatar
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2 votes
2 answers
227 views

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 ...
ultracold's user avatar
2 votes
2 answers
503 views

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 ...
Kurt Hikes's user avatar
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