All Questions
26 questions
5
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1
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98
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Why is it that for light elements, roughly up to iron ($\rm Fe$), splitting nuclei actually costs energy, rather than energy being released?
I have read this question:
For light elements, roughly up to iron ($\mathrm{Fe}$), splitting atoms actually costs energy, rather than energy being released.
How much energy is released from the ...
- 29.3k
0
votes
1
answer
50
views
Why do elements heavier than calcium require more neutrons to remain stable? [duplicate]
In studying the periodic table, I noticed that calcium (with atomic number 20) is the heaviest element with stable isotopes with a 1:1 ratio of protons to neutrons. For elements heavier than calcium, ...
- 3,199
15
votes
3
answers
6k
views
Are elements above 137 possible?
I have heard the argument that elements with atomic numbers above 137 are not possible but I am unsure if it's true or why.
- 630
1
vote
1
answer
109
views
Why does fission of large nuclei always result in energy released?
When large nuclei undergo fission, the binding energy per nucleon of products is greater than the binding energy of the original nuclei. This only happens (with certainty) when the products are Iron-...
- 11
11
votes
2
answers
3k
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Is there proof for: "Elements heavier than iron will decay to iron by processes such as fission and alpha emission"?
Freeman J. Dyson in his "Time without end: Physics and biology in an open universe", Lecture 2: Physics, part G: All matter decays to iron, claimed that on a long enough time scale "...
24
votes
1
answer
5k
views
Why is helium-4 the only nuclide with a negative nucleon binding energy?
He-4 is very unusual as it’s the only nuclide that does not accept another nucleon. In other words, even if you force a proton or a neutron into He-4, it will be kicked out immediately. If you ...
- 1,537
2
votes
0
answers
77
views
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 ...
- 21
1
vote
0
answers
49
views
Why can't massive nuclei combine together to release energy
I am basically confused as why can't larger nuclei undergo fushion and release energy. One reason I know is because of too much protons than neutrons which generates stronger electrostatic repulsive ...
- 11
0
votes
0
answers
100
views
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,...
0
votes
0
answers
43
views
How does the increased binding energy per nucleon help in stability?
I have some read answers on this forum, some books like Halliday Resnick and my course books. I have understood that binding energy is the energy we need to supply to break nucleus into individual ...
- 1
3
votes
1
answer
657
views
Does every element have a critical mass?
We have all heard of critical mass for radioactive materials like Uranium, Plutonium etc. but does every element theoretically have a critical mass? If not, what determines if such a phenomena is ...
- 630
1
vote
0
answers
41
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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 ...
- 3,001
2
votes
3
answers
2k
views
Mass per nucleon graph
I am a high school student and am struggling with understanding the significance of the mass per nucleon graph.
What does this graph show with regard to nuclear reactions? (y-axis: M/A, x-axis:A) I ...
- 647
4
votes
0
answers
76
views
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 ...
- 1,537
3
votes
2
answers
318
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 ...
3
votes
2
answers
1k
views
Why do elements, as they have more protons, need a higher amount of neutrons to stabilise them? [duplicate]
I've seen the graphs of the stability line but I can't find any reason as to why this happens, I understand radiation, just not why radiation needs to occur in the first place if that makes sense.
- 49
6
votes
1
answer
2k
views
Is there a highest possible atomic number?
I know that atoms with higher atomic numbers tend to become more and more unstable and decay quicker the higher the atomic number goes. Is there a limit to this where the time it takes for the atom to ...
- 203
-2
votes
1
answer
107
views
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 ...
- 99
10
votes
3
answers
1k
views
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 ...
- 209
1
vote
2
answers
104
views
Island of Stability in Astronomical Surveys
To the segment of nuclear physicists that predict that there is indeed an “Island of Stability” in super-heavy transuranic elements, where these atoms shouldn’t suffer the effects of radioactive ...
- 487
4
votes
2
answers
879
views
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?
- 167
23
votes
4
answers
16k
views
Can there be an atomic nucleus where there are more protons than neutrons?
As far as I know, number of protons is less that or equal to the number of neutrons in any atomic nucleus.
But is there any possibility that there exists a nucleus where the number of protons exceeds ...
- 437
1
vote
1
answer
133
views
Finding stable superheavy elements
Finding new stable superheavy elements is big interests in nuclear physics.
Nuclides with $Z>92$ are not found in nature, but can be made artificially.
Usually these nuclides become more unstable ...
- 305
4
votes
2
answers
1k
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Why is Helium 4 so stable?
I've been looking at stuff to do with binding energies and was wondering why Helium 4 is so stable. The fact everything up to carbon is less stable seems a bit odd. Is there a reason for this or ...
- 43
12
votes
2
answers
1k
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Is this a correct demonstration for why elements above untriseptium cannot exist?
With the confirmation that elements 113, 115, 117, and 118 are indeed fundamental elements that are now to be named on the periodic table, the next question is: what is the highest atomic number ...
- 444
4
votes
1
answer
1k
views
Why is Silver-108 unstable?
Why is Silver-108 unstable if silver-107 and silver-109 are stable?
I found it on crash course but no answer was given.
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