So far the largest element we as humans have made is oganesson, with 119 protons and electrons. But we can go bigger. The question is, how much bigger? Can we do 120 protons? 200? 1000? I'm just curious because because I haven't read much on the laws of general relativity and I'm bored

It's been like 4 years since my last post 💀

I can merge replies????

When did that happen?

One issue is that really heavy nuclei don’t remain intact for very long. There might be some isotopes that are longer-lived at the next magic number (filled shell) of neutrons and/or protons. Pb-208 is doubly-magic, with 82 protons and 126 neutrons, and is the heaviest stable isotope.

“Further predicted magic numbers are 114, 122, 124, and 164 for protons as well as 184, 196, 236, and 318 for neutrons.[1][4][5] However, more modern calculations predict 228 and 308 for neutrons, along with 184 and 196.”

https://en.m.wikipedia.org/wiki/Magic_number_(physics)

So that’s where to look. We’ve seen 114 protons.

 

Arguably, any neutron star is a giant nucleus, continuously changing the number of protons contained, but on a percentage basis, not by much. It is the Pauli exclusion principle which supports their stability, not so much any particular 'balance of forces'.

Somehow I think this reply is not what the OP was looking for.

7 minutes ago, Halc said:

Arguably, any neutron star is a giant nucleus, continuously changing the number of protons contained, but on a percentage basis, not by much. It is the Pauli exclusion principle which supports their stability, not so much any particular 'balance of forces'.

Stability of a neutron star is due to balance between gravity and degeneracy pressure, rather than any kind of arrangement between QCD and QED, which is what gives stability to nuclei.

Gravity, OTOH, plays no significant role in stability of nuclei. So a neutron star cannot be (sensibly) to be just a giant nucleus, IMO.

21 hours ago, joigus said:

Stability of a neutron star is due to balance between gravity and degeneracy pressure

Better worded, thanks.  The wiki site explains the pressure, due to electrons not being classical particles:

"The pressure exerted by the electrons is related to their kinetic energy. The degeneracy pressure is most prominent at low temperatures: If electrons were classical particles, the movement of the electrons would cease at absolute zero and the pressure of the electron gas would vanish. However, since electrons are quantum mechanical particles that obey the Pauli exclusion principle, no two electrons can occupy the same state, and it is not possible for all the electrons to have zero kinetic energy. Instead, the confinement makes the allowed energy levels quantized, and the electrons fill them from the bottom upwards. If many electrons are confined to a small volume, on average the electrons have a large kinetic energy, and a large pressure is exerted."

Yes, the degeneracy pressure is what supports the stars, and the effect is related to the Pauli exclusion principle.

 

My point still stands: Such large dense things squashed together by gravity are arguably a single nucleus of some unfathomable element. It certainly isn't a collection of small separate atoms that are just really close to each other. For one, the one large atom has far higher neutron-to-proton ratio than any known element. It's a low-energy solution to the otherwise problem of where to go with all the extra electrons forming the degeneracy pressure.

2 hours ago, Halc said:

Better worded, thanks.  The wiki site explains the pressure, due to electrons not being classical particles:

"The pressure exerted by the electrons is related to their kinetic energy. The degeneracy pressure is most prominent at low temperatures: If electrons were classical particles, the movement of the electrons would cease at absolute zero and the pressure of the electron gas would vanish. However, since electrons are quantum mechanical particles that obey the Pauli exclusion principle, no two electrons can occupy the same state, and it is not possible for all the electrons to have zero kinetic energy. Instead, the confinement makes the allowed energy levels quantized, and the electrons fill them from the bottom upwards. If many electrons are confined to a small volume, on average the electrons have a large kinetic energy, and a large pressure is exerted."

Yes, the degeneracy pressure is what supports the stars, and the effect is related to the Pauli exclusion principle.

I don’t think that’s the whole story; forcing the electrons to combine with protons to form neutrons requires energy. You have the degeneracy pressure until you can do that. Or at least, that’s how I understood it.

35 minutes ago, Halc said:

However, since electrons are quantum mechanical particles that obey the Pauli exclusion principle, no two electrons can occupy the same state, and it is not possible for all the electrons to have zero kinetic energy.

Not central to what we're discussing, but this is a flawed explanation of why electrons --or neutrons for that matter-- cannot have zero kinetic energy. Quantum particles cannot have zero kinetic energy due to Heisenberg's uncertainty principle, not to Pauli's exclusion principle. So any fermions must always have some kinetic energy in any given reference frame. Never mind other identical fermions being around. This is called ground-state kinetic energy or zero-point KE, and it's the least KE any particle can have. Were fermions allowed to have 0 KE because x,p were not complementary (HUP for position and momentum), they could still be at different places and still PEP would not be violated.

What fermions cannot ever do is be in the same quantum state with however much kinetic energy HUP allows them to have.

42 minutes ago, Halc said:

My point still stands: Such large dense things squashed together by gravity are arguably a single nucleus of some unfathomable element. It certainly isn't a collection of small separate atoms that are just really close to each other.

Glueballs aren't either. Yet nobody says glueballs are neutron stars just because they're not bunches of atoms. Things are not only defined by what they're not.  Tritium isotopes are not "tiny neutron stars" either.

Degeneracy pressure is not electrostatic repulsion, and gravitation has nothing to do with gluons and other ephimeral QCD states going back and forth between nucleons, which is what makes nucleons stick together by QCD. It's a very different animal.

Neutron stars do not undergo fission via beta decay, as nucleons do. They do not have magic numbers. They do not have the same scattering properties, they don't have a definite spin statistics. Merging of neutron stars is nothing like nuclear fusion... And so on.

\(\sim\)10⁵⁷ neutrons packed together by gravity against Pauli's exclusion principle is what we call a neutron star

\(\sim\)10² neutrons+protons packed together by QCD virtual states against electrostatic repulsion is what we call a nucleus

The difference in name is justified because the phenomenology, what makes them, and most everything else, is different enough that it merits a different name.

Perhaps this way  ?

Even if not the pictures are pretty.

https://www.chemistryworld.com/news/hand-built-caesium-based-artificial-atoms-used-to-create-synthetic-benzene/4017567.article

 

On 8/9/2024 at 6:49 PM, joigus said:

Not central to what we're discussing, but this is a flawed explanation of why electrons --or neutrons for that matter-- cannot have zero kinetic energy. Quantum particles cannot have zero kinetic energy due to Heisenberg's uncertainty principle, not to Pauli's exclusion principle. So any fermions must always have some kinetic energy in any given reference frame. Never mind other identical fermions being around. This is called ground-state kinetic energy or zero-point KE, and it's the least KE any particle can have. Were fermions allowed to have 0 KE because x,p were not complementary (HUP for position and momentum), they could still be at different places and still PEP would not be violated.

What fermions cannot ever do is be in the same quantum state with however much kinetic energy HUP allows them to have.

Glueballs aren't either. Yet nobody says glueballs are neutron stars just because they're not bunches of atoms. Things are not only defined by what they're not.  Tritium isotopes are not "tiny neutron stars" either.

Degeneracy pressure is not electrostatic repulsion, and gravitation has nothing to do with gluons and other ephimeral QCD states going back and forth between nucleons, which is what makes nucleons stick together by QCD. It's a very different animal.

Neutron stars do not undergo fission via beta decay, as nucleons do. They do not have magic numbers. They do not have the same scattering properties, they don't have a definite spin statistics. Merging of neutron stars is nothing like nuclear fusion... And so on.

∼ 10⁵⁷ neutrons packed together by gravity against Pauli's exclusion principle is what we call a neutron star

∼ 10² neutrons+protons packed together by QCD virtual states against electrostatic repulsion is what we call a nucleus

The difference in name is justified because the phenomenology, what makes them, and most everything else, is different enough that it merits a different name.

(I'm getting headache fr)

13 hours ago, A Person Who Exists said:

(I'm getting headache fr)

A neutron star is not an atom, IMHO. Swansont's answer gives you all you need to know.

I've read about this somewhere,

Apparently any elements above 118 protons are too unstable to even exist, Oganesson's most stable Isotope (Oganesson-294) only has a half life of around 0.89 milliseconds.The problem with elements with a proton amount higher than 118, is that due to the increasing repulsive forces between protons in the nucleus, the nuclear force holding due the nucleus together is overwhelmed and starts decaying rapidly. This causes elements above a 118 proton count to be extremely unstable; however, scientists studying this topic guess that above 118 protons there is an "island of stability" (around 114 protons and 184 neutrons) wherein super-heavy elements have longer half times than exhibited by their neighbors. While as of current times no element beyond 118 protons have been synthesized, the fact that elements with 118 protons even exist and also that their lifetimes increase when approaching the hypothetical island, is promising evidence.

Attached here is a diagram.

4 hours ago, metreosci said:

Apparently any elements above 118 protons are too unstable to even exist, Oganesson's most stable Isotope (Oganesson-294) only has a half life of around 0.89 milliseconds.

And it has 119 protons, which is at odds with your first sentence.