Questions tagged [isotopes]

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Can Carbon-14 be naturally produced on Earth at low altitudes, ground level and even underground?

If so, what will the C-14 production yield depend on? Thank you!
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51 views

Can 40Ca II decay or change into something different

I just read the Wiki article on calcium isotopes and it said the stable calcium isotopes such as 40Ca have never been observed to decay. Then, despite the high temperature of stars such as Sun there ...
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1answer
56 views

Why is cobalt-57 radioactive? Why isn't it stable?

Cobalt-57 should be the most stable and common isotope of cobalt, right? It has three more neutrons than protons.... Nickel-58 only has two more neutrons than protons, and it is the most common/...
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Why Lithium-3 mass supposedly exceed hydrogen mass per nucleon?

When I check this list of isotopes or even this one, I can find that the mass of lithium 3 per nucleon would be higher that the one of hydrogen, that is, the binding energy would be negative: ...
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33 views

Isotopes: boundary between very short life time and not existing at all? [duplicate]

We know of some isotopes with extremely short half-lives e.g. from Isotopes of hydrogen at Wikipedia, I see $^4H$, $^5H$, $^6H$, and $^7H$ with half-lives of the order $10^{-22}s$. Is there an ...
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Density of solids and liquids composed of different isotopes

In this question, I am only considering conditions fairly close to STP and moderately but not extremely high accuracy. E.g. a quite well equipped school laboratory. For gases, the density will be ...
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20 views

Temperature dependency on $D_2O$ stratification

The original problem is the research of low energy consuming process to take away D2O from drinking water. Reading the Q&As on this post, particularly the answer provided by @DjohnM, I would like ...
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1answer
51 views

How to transform activity ratio to isotope ratio? [closed]

I am given a table that describes an ancient spillage of spent nuclear fuel: ...
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23 views

In what cases do isotopes cause non-negligible effects in chemicals

For example, CO2 (carbon dioxide), there could be Carbon8-Carbon22 isotopes, and I'm not sure for oxygen. Wondering at what point there is some sort of non-negligible effect, and what the effect(s) ...
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45 views

If we need the term/concept of “isotope”, or why we call them “elements” of the periodic table

I just read this: A nuclide is a species of an atom with a specific number of protons and neutrons in the nucleus, for example carbon-13 with 6 protons and 7 neutrons. The nuclide concept (...
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1answer
191 views

Why is the isotope of lead-206 stable against alpha decay?

The mass of Lead-206 is larger than that of Mercury-202 + Helium-4. Why is then Lead-206 stable against alpha decay? I have heard that the beta-decay can stabilize a nucleus against alpha decay, and ...
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1answer
54 views

Stability of isotopes

Yesterday I was looking at the semi-empirical mass formula and calculating some binding energies of specific nuclei. Eventually I came across this website that listed both total binding energies per-...
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Bare Critical Masses of $^{241}$Am, $^{242m}$Am, $^{238}$Pu and $^{242}$Pu

$^{238}$Pu has 144 neutrons, and it has 2.8$\times$10$^{3}$ g$^{-1}$.s$^{-1}$ spontaneous fission neutrons and bare critical mass in 10 kg. $^{242}$Pu has 148 neutrons, and it has 1.7$\times$10$^{3}$ ...
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Tritium decay energy too small for quark model

So $^3$H turns into $^3$He through $\beta^-$ decay, right? The energy of this reaction is only 18.6 keV. However, according to the constituent quarks model, the only thing different between $^3$H ...
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3answers
49 views

Clarification on isotope notation

I am a bit confused about the idea of isotope notation. I know that the top number is the mass number, equivalent to the number of neutrons + protons, while the bottom is the atomic number, equivalent ...
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Has there been any R&D(let alone progress) in the development of gamma voltaic cells?

I ask this because it is my understanding that gamma rays form ion tracks and oxygen radicals when gamma emitting material is immersed in an aqueous solution. Cesium-137 is a very strong gamma ray ...
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1answer
69 views

How many known nuclides are there?

What is the current estimate for the number of nuclides? This is a very basic question, but I'm finding it remarkably hard to get a reliable, up-to-date answer. A few books published in the last 2-3 ...
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2answers
66 views

What is the time for sufficient decay of plutonium to render an implosion type fission bomb ineffective

Plutonium decays leaving helium. In a mass of metallic plutonium, some of the metal will decay resulting in helium. This makes the plutonium spongy after time. Presumably this sponginess would ...
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1answer
144 views

Why are higher magic numbers not accurately predicted if nuclear potential is assumed to be a central potential?

Nuclei with magic numbers have a higher stability that those without. If we think of the nuclear potential as a central potential though these magic numbers aren't predicted accurately. Why is this so?...
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1answer
238 views

Should Copper 65 and Copper 63 isotopes have a larger density than a copper 29 atom?

I was looking at the first page of a paper (see https://aip.scitation.org/doi/10.1063/1.1735598#Metrics-content for details) and I ran across something odd. According to the paper, Copper isotopes 63 ...
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1answer
33 views

How is the iron isotope Fe(72) generated? [closed]

Does 72Fe occur naturally? Either way, can it be produced synthetically and if so, how?
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1answer
60 views

Are there radioactive elements that can be seen to diminish/change with the naked eye?

That is, after creating a quantity of a radioactive isotope with a half-life of several seconds or minutes, could the sample be seen to change into decay products with the naked eye? (Excluding ...
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2k views

Why doesn't hydrogen have a neutron?

Why doesn't hydrogen have a neutron?
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1answer
428 views

What is the difference between autoradiography and scintillation counting?

How are the two techniques different? To the best of my understanding, both autoradiography and scintillation counting both depend on the radioactive emission of electrons (or photons) interacting ...
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878 views

Highest Binding Energy per Nucleon

According to Wikipedia Isotope of nickel has the highest binding energy per nucleon. But according to a statement in the standard textbook of our country it is said that Fe has the highest binding ...
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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 ...
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109 views

Carbon transformation in nuclear reactors

In a nuclear reactor, does stable carbon 12C in graphite rods turn into unstable 14C? If so, is it because of induced radioactivity?
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What isotope has the highest mass that does not have spontaneous fission

What is the highest mass isotope that does not undergo spontaneous fission? In deed I assume it would highest atomic number isotope that decays by other processes.
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1answer
243 views

How to Calculate Instantaneous Decay

If I want to calculate the number of moles/sec decayed of a substance, and I know the number of moles of isotope and the half life, would I then use the following? $$N/s=N_0e^{1/\tau_{1/2}}$$ Where $...
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1answer
266 views

Which is the most toxic isotope of plutonium and what makes it toxic? [closed]

Some sources say plutonium is one of the most toxic substances known, while this challenge from Bernard Cohen to Ralph Nader challenges the toxicity. I heard that only one of its isotopes is toxic, I ...
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3answers
120 views

Why does a particular radioactive decay chain terminate at the same isotope regardless of different decay paths

If we start with a particular unstable isotope and this begins a decay chain, and if at some steps along the way the parent nuclide can decay by either beta or alpha decay, why is it that we end up ...
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1answer
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How to calculate isotopic power of radon?

I read that radioisotope thermoelectric generators run off of isotopes that produce alpha particles. I see that various fuels such as polonium-210 are categorized by "isotopic power". Radon is not ...
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1k views

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 ...
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What process was used to produce heavy water at the Norsk Hydro plant in Vemork Norway? [closed]

All references I have browsed for this Norsk Hydro plant mention very little on the actual heavy water production process used. I understand that this plant was adjacent to a power station that had a ...
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1answer
321 views

Can heavy water be isolated with water centrifuges?

If a container of pure water is rotated fast enough at high rpm, would $\mathrm{D_2 O}$ separation be feasible? Another way to ask is: it practically and physically possible with current technology ...
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2answers
378 views

Is decay heat proportional to half life?

I know different isotopes decay at different rates. The rate for a given isotope is given by its half life. I know heat is produced by decay events. I know it is bad form to put 2 questions in one ...
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3answers
4k views

Why is caesium-137 more stable than caesium-134?

Caesium-133 is stable. Caesium-134 and caesium-137 are radioactive isotopes of caesium with half-lives of 2.065 years and 30.17 years respectively. Why does caesium-137 have a longer half-life if it ...
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182 views

Heavy-oxygen water melting and boiling points

What is heavy-oxygen water (O-17 and O-18, both if possible) melting and boiling points? I already search it on the web, but the only result I can get is this one: http://www.chemicalbook.com. They ...
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100 views

Can an isotope emit only Beta radiation? Or is gamma radiation always emitted alongside beta?

If so, what isotopes only emit beta radiation? Thanks!
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2answers
542 views

Why do GM Detectors do not pick up Betas from Co-60 Nuclide

This questions is about radioactive Isotopes. My current problem is, how can i "pick" isotopes, that only emit a specific type of radiation. Here is an explanation of my problem: Cobalt-60 (Co-60) ...
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1answer
304 views

How are neutrons absorbed by sodium in a nuclear reactor?

I read online that liquid sodium is used as a coolant in nuclear reactors. it was written that: "Sodium-23 is the only stable isotope of sodium but sodium absorbs neutrons to form sodium-24 isotope ...
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1answer
136 views

Where does the tritium on the Earth come from?

As tritium has smaller lifetime than the life of the Universe, it should have decayed before the present age completely. How can the presence of natural tritium be explained in that case?
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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 ...
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2k views

Why are there no stable isotopes with an atomic mass of 5 or 8?

One of the things I've encountered in my travels is the mass-5 roadblock. Rod Nave writes about it on his excellent educational hyperphysics website: The helium-4 nucleus or alpha particle with a ...
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484 views

Metallic deuterium and metallic tritium as a fuel instead of metallic hydrogen?

A lot of news come these days about metallic hydrogen and its possibility of releasing 20 times more energy than just oxygen-hydrogen reaction. Like here: https://www.nasa.gov/pdf/...
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About the Stability of hydrogen Isotopes

Shouldn't tritium be more stable than a hydrogen atom with no neutrons? Why does tritium do alpha decay but not hydrogen atom with no neutrons? I suppose that when the number of neutrons increases the ...
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2answers
217 views

Physical limit for the shortest possible half-life?

This question comes from observation that there are no known half-lives in range; $1\times 10^{-10}$ seconds to $1\times 10^{-21}$ seconds. (Except Beryllium-8, which has a half-life of o $7\times 10^{...
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Uranium of galena removed T years ago using Pb-Pb dating [closed]

So we have an equationn for Pb-Pb dating: $$\rm \frac{\frac{207Pb}{204Pb}-\left(\frac{207Pb}{204Pb}\right)_0}{\frac{206Pb}{204Pb}-\left(\frac{206Pb}{204Pb}\right)_0}=\frac{235U}{238U}\cdot \frac{e^{\...
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4k views

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?
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Half-life of 178m2 Hafnium isotope

Why is the half-life of 178m2 Hafnium isotope 31 years? Maybe it is somehow related to its nuclear spin (16+)?