/sci/ - Science & Math

>>8246733
Who told you it doesn't?

take your cl/a/ssic particles back to >>>/a/ pedophile

this dude may be meming, but I wonder about this.

well fuck..

>>8246779
>>8246805

If you consider the orbit of electrons, the angular velocity of the electron cancels out the force from the magnetism.

If you consider it under quantum mechanics, then spin,charge and angular momentum are non physical properties needed to describe the probability density of the electron.

There is a non zero chance for it to appear in the nucleus, but it doesnt happen.

The electron goes through the nucleus all the time. Is there a problem with that statement? It's not like it stays there very long.

>>8246733
It's called the Strong Jesus Force.

a dark force

jk its called strong force and its very well understood

>>8246734
>>8246819

these guys know what they're talking about

the wave function predicts that for an atom the elctron density should be highest at the nucleus and therefore you should find an electron there. However, we know that cannot be true by simply observing the way electrons are exchanged and shared between atoms. The electron density is largest nearer the nucleus, sure, but it is not there. This is one of the odd observations of quantum mechanics similar to the idea of "nodes" where the probability of finding an electron is zero, yet electrons seem to pass through them.

As far as many electron atoms go, the electrons in shells beyond 1s experience an attraction due to the nuclear charge and a repulsion away due to the electrons closer to the nucleus. The net attraction an electron beyond the 1s orbital feels is called the "effective nuclear charge" which is calculated simply by

Effective nuclear charge = nuclear charge - electron repulsion.

using Slater's rules, you can make a pretty close estimate to what that number is.

>>8246853
>muh Zeff
Take your physic/a/l chemistry back to >>>/a/ pedophile

>>8246853
>the wave function predicts that for an atom the elctron density should be highest at the nucleus and therefore you should find an electron there.

Not exactly. The wavefunction for 1s looks like [math]e^{-r/a}[/math] but to find the probability you have to calculate the integral which includes an [math]r^2[/math] in the integrand.

Pic related illustrates the actual radial variation of the probability density of the 1s orbital.

>>8246853
>the wave function predicts that for an atom the elctron density should be highest at the nucleus and therefore you should find an electron there

This is not true in the slightest. You should remember that the radial probability density function is multiplied by a factor of r^2. In fact, for a simple Hydrogen-like atomic model, it's 1s state probability density function is just r^2 damped by an exponential to give a peak at the effective Bohr radius. For small radius values, the exponential is effectively 1 and all of the scaling is in the r^2 term--which vanishes at the center. Like >>8246863 demonstrated.

>similar to the idea of "nodes" where the probability of finding an electron is zero
The probability of finding the electron in a measure zero region of space is zero. No matter where you look in a simple Hydrogen atomic model--or even any similar quantum mechanical problem--the probability of finding the particle within a region vanishes as you squeeze the region into a point/plane. You can't talk about the probability of an electron existing at a point in this formalism. You can demonstrate that, for example, the electron being within a suitable fixed radius ball near a zero of the probability density has much smaller probability than some other location within a Bohr radius or so.

>>8246733
If unlike charges attract, why doesn't the electron fly into the proton?
If massive bodies attract, and the Sun and the Earth have mass, why doesn't the Earth fly into the Sun?

>>8246862

I'm curious. Is this just one dedicated troll doing the "go back to /a/ pedophile" bit, or is that a meme here now?

>>8246863
>>8246865

my pchem is rusty. sorry for acting like i knew what i was talking about.

>>8246867
1 autistic young memester

>>8246903
Dumb frogposter

>>8246733
If the electron were localized at the proton, the uncertainty in the electron's momentum becomes sufficient for the electron to escape the potential well formed by the proton. The proton can be well localized in the nucleus because it is orders of magnitude heavier than the electron.

>>8246733
https://en.wikipedia.org/wiki/Electron_capture

Leptons, quarks and all that shit

>>8246733
>>8246779
This is literally question that spawned quantum mechanics. classically atoms dont work, even basic QM solves this problem.

>>8246831
>>8246837
Electron don't interact with the strong force.

>>8246865
>If unlike charges attract, why doesn't the electron fly into the proton?
If massive bodies attract, and the Sun and the Earth have mass, why doesn't the Earth fly into the Sun?
That's a false equivalence - moving charges radiate, but moving masses don't (in Newtonian gravity at least).

>>8246733
What if they do, but they just stop being matter when they do it?

>>8247628
>What if they do, but they just stop being matter when they do it?
that would be observed but is not.

>>8246733

Or maybe it's orbiting the nucleus so fast, it won't fall in it, like how moon around Earth?

Think about that

The variation in a physical coupling constant under changes of scale can be understood qualitatively as coming from the action of the field on virtual particles carrying the relevant charge. The Landau pole behavior of quantum electrodynamics (QED, related to quantum triviality) is a consequence of screening by virtual charged particle-antiparticle pairs, such as electron-positron pairs, in the vacuum. In the vicinity of a charge, the vacuum becomes polarized: virtual particles of opposing charge are attracted to the charge, and virtual particles of like charge are repelled. The net effect is to partially cancel out the field at any finite distance. Getting closer and closer to the central charge, one sees less and less of the effect of the vacuum, and the effective charge increases.

>>8247680

If an electron couldn't move, would it then fall into the proton?

>>8247676

Hey Niels, long time no see.

>>8246733
While electrons and protons are attracted to each other, both of them know realistically it just wouldn't work out.

>>8247697
No, because that would mean it's moving, which you said it isn't.

>>8246733
They do. Theyre called neutrons.

Holy fuck it's like no one took a basic chemistry class in this thread.

>>8247490
No. Ultraviolet Catastrophy.

What happens when an electron touches the nucleous?

Some poeple talked about angular velocity here, but why would an electron have velocity in the first place?
Does an electron ever collide with anything and stop?

>>8248770
wrong

Part of the problem is quantum mechanics.

An electron does not orbit a nucleus as you would classically think. Yes electrons have angular momentum, but again not in the classical sense. The picture you posted is not at all how atoms look or operate.

A classical interpretation, again not entirely accurate, would tell you that it doesn't fall due to its speed.

Next time google it, not hard to do.

>>8250001

What's the correct interpretation then, if the picture of OP's is wrong?

>>8248219

It won't fall to the nucleus because it's not moving and it won't fall to the nucleus because it's moving?

Op here. Read and reread this thread. Not a single answer explains why it doesn't happen beyond "it can't happen because it hasn't been observed/the model doesn't allow it"

wtf

>>8250059

The fact is, it doesn't fall to the nucleus, why do we have to explain the reason?

We have never claimed it has to fall to the nucleus because we say so, observations tell electrons don't behave that way.

>>8250063
So unlike charges attract until they hit a magical wall surrounding the proton and I'm just supposed to accept this as making sense?

>>8250068

No one ever said it's a magical wall, all we can say from observations is that for some reason the electron doesn't fall to the nucleus.

And we have determined that charges attract too. It's all just observations, those don't have to make sense.

The nature doesn't give a fuck it makes sense or not, we are just observing it.

>>8246733
>why doesn't the earth fly into the sun?

>>8250095

Because it moves fast enough to avoid that, same thing for the electron?

>>8250105
But don't orbits eventually decay? Won't the moon come crashing into the earth one day?

Plus afaik electrons don't orbit the same way planets orbit a star

>>8250108

Remember that an atom is mostly just empty space, like the space between Sun and Earth.

And yes, we call it heat death, the bitter end.
Not entirely sure how fundamental particles will pay part in that as we know them,
but we are not here to witness that happening.

Also movement doesn't mean you need energy for it, for acceleration to other direction is needed, slowing down and speeding up as we call them.

>>8250108
>Plus afaik electrons don't orbit the same way planets orbit a star

>electrons

>orbit
i thought this was a board for learned people

>>8250117

You thought wrong,
you seriously need to become better at thinking.

Respect to all people who want to gain more knowledge and find more information, learn etc

>>8250095
Sun is in motion; planets trail/drag behind. Is that what >>8250001 is saying? Electron drags behind moving proton? And does anyone know if there is some repulsive force protons exert on electrons in addition to their attractive forces?

>>8250123

I don't actually know the answer, but I know this much:

Applying analogies from the macro world to the realm of quantum physics is rarely useful.

Forget about orbits, planets, etc. Those work on gravity, which is so tiny as to be nonexistent at the subatomic level. Things act in weird and unintuitive ways at that size. Asking why the electron doesn't crash into the proton is a good question, but comparing it to a planet around a sun is not useful.

The terms don't really help, either. "Spin" and "angular momentum" don't actually mean the same thing as they do in the macro world. They're just properties these objects have, and those properties cause certain behaviors. Don't think of "spin" as "this object is rotating on an axis."

Now, can we get someone who has actually studied quantum mechanics to answer the original question?

>>8250144

What for do we need to know the why?

>>8250144
I thought it might be a fitting analogy since the sun's core is also positively charged while it's surface is negatively charged, and both the sun and proton are moving. But who knows

>>8250156
Of course we don't need to know. We just like to know and that's enough to discuss it.

>>8250123
What I think the other anon was trying to say is that electrons don't orbit the nucleus as a planet orbits the sun. With planets they have well defined positions and momenta, so it becomes a case of just balancing the attractive force with the centripetal force. In Quantum mechanics position isn't well defined, what this means is that the wavefunction has a term that looks like [math] exp \left ( -r / a \right ) [/math], but that terms is non-zero everywhere so we can, at least in principle, find the electron anywhere (yes including within the nucleus). The standard interpretation of this is that electron exists in all possible states until it's measured, only then does it take on a definite position, the most probable place to find it is at 3a/2.

>>8250162

Well I do want to know the why too, but talking here about it doesn't help us to find answers to it..

What kind of experiments could we do to find the why, what do you think?

>>8246733
>If unlike charges attract, why doesn't the electron fly into the proton

They do. We just perceive the universe in super slow mo. The universe is just momentarily stable and will annihilate itself instantaneously. We just perceive time so slowly that it appears to not be happening.

Ez peezee.

>>8246733
If masses attract each other, why doesn't the moon accelerate towards the earth?
>pro tip: it does

>>8250183

How can you prove that claim?

>>8250195
It just werks :^)

>>8250194

> Accelerate towards Earth
Yea, because moon totally doesn't move towards Earth either, but moves away from it slowly.

If you want the simplified answer, it's because energy levels are 'quantised', i.e. discrete not continuous. Moving closer to the nucleus would cause the electron to lose potential energy and 'at' the nucleus it would have zero energy. However, even the ground state of any system has energy and so the lowest possible energy level the electron can exist in corresponds to the electron still not being 'at' the nucleus.

This is as close a reason as I can give you without delving into the maths as other anons have, but ultimately that's what you have to do because quantum objects do not behave analogously to macroscopic objects. There is no physical equivalent you can look at and reason about, they're more or less purely mathematical objects and this is one of the main barriers to understanding the subject.

Also this thread just confirmed my suspicion that the majority of posters on /sci/ have little or no scientific understanding if no one even passingly mentioned energy levels yet.

>>8250156

"Why" is a question that leads to better understanding. There's usually an answer.

If no one asked why nuclei stick together even though protons repulse each other, we'd never have discovered the strong force.

I realize this is QM and there may not be a "why." It never hurts to ask.

>>8250213

And this anon >>8250211 just answered it.

>>8250211
>Also this thread just confirmed my suspicion that the majority of posters on /sci/ have little or no scientific understanding if no one even passingly mentioned energy levels yet.

It's funny since the reason you posted is completely wrong, there is a nonzero probability of finding the electron within the nucleus.

>>8250211
>Also this thread just confirmed my suspicion that the majority of posters on /sci/ have little or no scientific understanding if no one even passingly mentioned energy levels yet.

Why would that need to be need to be brought up? In classical mechanics, OP's intuition, the system still wants to minimize energy but there is no lower bound due to the 1/r^2 singularity. The theory breaks down at short distance scales. For weak and linear fields like electromagnetism the uncertainty principle in quantum mechanics is enough to solve this problem which many posters have either directly or indirectly mentioned.

>>8250211

>Also this thread just confirmed my suspicion that the majority of posters on /sci/ have little or no scientific understanding

Some of us are just interested in science from a layman's point of view. I took two years of chem in high school and physics in college, but I was a CS major and all that was a really long time ago. I've got an interest without the benefit of the education to go with it. I do try not to answer questions I'm not sure about, though.

It'd certainly be nice if there were more people who actually knew what the fuck they were talking about in here, though.

>>8249526
Does energy ever die?

>>8249526
Von Neumann was working on an electron bomb but CIA killed him by giving him cancer because the electron bomb was powerful enough to destroy the globe.

>>8250232
Nothing he said contradicts that. Are you retarded?

If greater mass attracts lesser mass, why don't we slam into the sun?

>>8250293
We will, eventually.

>>8250296
[citation needed]

>>8250293
draw a force diagram of a small ball orbiting a big ball and you'll notice. the force points inwards but the movement is perpendicular to the force

>>8250296
Not in a billion years GOY :∆D

>>8250290
Are you?
>However, even the ground state of any system has energy and so the lowest possible energy level the electron can exist in corresponds to the electron still not being 'at' the nucleus.

Ignoring the fact that the ground state has very little to do with the location of the electron, the implication here is that at the even at the lowest energy level the electron will always be outside the nucleus. It reads likenit was written by someone with a passing familiarity with oldn quantum theory at best.

>>8250307
>the implication here is that at the even at the lowest energy level the electron will always be outside the nucleus

What a dumb non-sequitur. An electron isn't a little ball.

>>8250300
The sun has a reach greater than all the fucking planets. We supposedly have comets leaving the solar system only to return precisely as predicted decades later when the sun has moved across the galaxy and we are brainwashed into thinking that everything occurs randomly and it's all pure coincidence.

I think the heliocentric model is bullshit. More like Helios n' trick.

>>8250315
And yet that's what the other guy implied. Obviously it's wrong.

How does carbon dating work if you don't know the original amount of radioactive carbon in the sample when it was made X amount of years ago?

Evolutionist btfo?

>>8250326
No he didn't. Work on your reading comprehension.

>science fags can't even answer a basic question about the most basic part of physics but expect me to believe the satanic theory of evolution
Literally CAN'T male this SHIT up

>>8250333
Yes he did. Allow me to break this down for you since you're clearly having trouble.
OP asked:
>>8246733
>If unlike charges attract, why doesn't the electron fly into the proton?

Anon answered:
>>8250211
To summarise:
>Because energy levels are quantised and a ground state ensure that an electron is always outside the nucleus

Clearly anon thinks two things:
>Energy levels are actual locations with an atom
And
>An electron will always exist outside of the nucleus

Both of these are wrong. Now we know he must think that otherwise its completely pointless post in the sense that it addresses nothing in the thread.

Further the actual answer to OP's question is:
>An electron has a nonzero probability of being found with in the nucleus.

The fact anon didn't say that and instead went off on a tangent about energy levels further reinforces that belief that he doesn't have clue what he's taking about.

>>8250317

You know, the thing that sucks about /sci/ is that's it's hard to tell if people like this are really this stupid or if they're just really good at making bait.

>fry.jpg

>>8250333
BTFO by >>8250350

>>8250356
Well you took the bait if I had a lure. So who the retard now.

>Anime-girl-with-lazy-eyes-doing-chest-beating-with-palsy-hands.gif

>>8250334
Found the retard

>>8250350
>>Because energy levels are quantised and a ground state ensure that an electron is always outside the nucleus
Haha, stopped reading there. Quit making up strawmen. It doesn't compensate for your inability to read.

>The fact anon didn't say that and instead went off on a tangent about energy levels further reinforces that belief that he doesn't have clue what he's taking about.
That an atom has nonzero ground state energy guarantees the electron cannot be localized at the nucleus. A normal 5 year old can do the math. Why are you so retarded?

>>8246733
https://van.physics.illinois.edu/qa/listing.php?id=1226

>>8250394
>https://van.physics.illinois.edu/qa/listing.php?id=1226
>it just kind of stops thanks to kinetic energy or some shit, idk why lol
>we don't pretend to understand why

>>8250389
>That an atom has nonzero ground state energy guarantees the electron cannot be localized at the nucleus.

But that's completely wrong. Take the hydrogen atom in its ground state, let b be the proton radius then [eqn] P(r \leq b) = \frac { 1 } { a^3 \pi } \int ^{2 \pi } _{ 0 } \int ^{ \pi } _0 \int ^{ b } _0 e^{ -2r / a } r^{2} \sin \left ( \theta \right ) dr d \theta d \phi [/eqn] Doing that trivial integral gives: [eqn] P(r \leq b) = 1 - e^{-2r/a} \left ( 1 + \frac { 2b } { a } + \frac { 2b^2 } { a^2} \right ) [/eqn] Let [math] \delta = 2b/a [/math] expanding in powers of delta and only taking terms of leading order leaves us with [eqn] P(r \leq b) = \frac { 4 b^3 } { 3 a^3 } [/eqn] taking [math] b \approx 10^{-15} [/math] gives [eqn] P(r \leq b) \approx 10^{-14} [/eqn]

Like I said a nonzero probability. Why do people insist on talking about shit they have no understanding of?

>>8250430
>a non-zero probability density at the nucleus = localization at the nucleus

Let me laugh even harder. How many extra chromosomes are you carrying around, retard?

>>8246831
This.

>>8250469
>Doesn't know what he's talking about
>Continues to talk

It's cute desu.

>>8250430

>why do people insist on talking about shit they have no understanding of?

Are you really that stupid you can't figure that one out?

> math makes made me smart

>>8250469
Except that's [math] \int ^{b} _{a} | \Psy | ^{2} dr [/math] which is the probability of finding the electron between a and b. This is literally page 2 of Griffiths, fuck sake anon you cretinous faggot, read a god damn book.

>>8246733
Consider this:
If unlike charges didn't attract, the electron wouldn't even go anywhere near the proton, let alone fly into it.

>>8250491

I've never met a smart human, who has called someone a faggot.

>>8250478
Projections are even cuter.

>>8250515
There's always the first time.

>>8250491
And the point of posting this high school platitude was what? To further emphasize your complete lack of understanding into what's being discussed?

>>8250529

Wasn't the first time, because he's not smart, rule applies.

>>8250430
Why does phi go to 2pi and not theta? I thought theta goes to 2pi and phi goes to pi.

>>8250538
>being tripped up this hard by simple change of symbols
hows that degree in triple integrals treatin' ya

>>8250542
Did I make an assertion that hurt your feelings?

Its just a question.

>>8250542
Y u mad, fuccboi?

>>8250544
why would my feelings be hurt, I got the privilege of studying under the great Jacobi Barnet

>>8250558
Jacob barnett, the autism kid?

>>8246733
Because electrons aren't actually point objects orbiting the nucleus. Electrons don't 'orbit' in any meaningful sense, and in fact there is a small but nonzero probability of finding an electron inside the nucleus. It's just sort of ... a delocalized blob, a standing wave in the electron field pinned at the center of the atom. (Electron orbitals are actually directly the same shape as spherical harmonics.)

Unfortunately, it's been way too long since I touched up on QM, but I think the reason it doesn't just collapse is due to one of the uncertainty relations? The smaller the space the electron is localized to, the higher the energy uncertainty, so the greater the possibility of escaping that space; the lowest energy level is an equilibrium between the two. Or...something like that.

>>8246819
>There is a non zero chance for it to appear in the nucleus, but it doesnt happen.

It does happen for certain kinds of radioactive decay.

>>8246819
>Magnetism

Lol no

Why are nanotubes so hard to make?

>>8246733
Because of the centrifugal force.

Isn't it because of meta-stability? The velocity of the particle is its "kinetic" energy and the area in which it resides is its "potential" energy. While the electron falls to a lower energy state (as it approaches the nucleus) in order to shed energy, at a certain point it would begin to gain more energy than it would lose if it continued to fall, so as not to invalidate the Heisenberg uncertainty principle. Eventually it finds a pocket which it can occupy that is stable, albeit not at ground level, unless imparted with more energy and released from orbit or driven into the nucleus and captured?
Also, as another question isn't this tangentially related to the whole Dirac Sea and negative energy thing? (why an electron would not just continue to lose energy by falling to lower and lower states even when it would mean it eventually fall into negative states that the Dirac equation proved could exist)

>>8252369
1. the ground state *is* the stable state between the electrostatic potential and zero-point energy - the solution is time-independent

2. only in the sense that nature likes to minimize its energy as much as it can. in spaces with large extra dimensions, the electrostatic potential is much stronger, the hamiltonian is unbounded from below with continuous spectrum from -\infty to +\infty, and the electron annihilates with the nucleus. redefinition of the vacuum here is just silly and would break even more things