A nucleus made of protons and neutrons surrounded by a cloud of electrons equal in number to the protons.

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4answers
3k views

How can one describe electron motion around hydrogen atom?

I remember from introductory Quantum Mechanics, that hydrogen atom is one of those systems that we can solve without too much ( embarrassing ) approximations. After a number of postulates, QM ...
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2answers
142 views

Why don't electrons collide among themselves

The Heisenberg principle states that we cannot ascertain simultaneously the position or momentum of any small particle. However slight, is there a chance that 2 or more electrons from the same or ...
0
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2answers
94 views

Resonate frequency of an object?

Below is a paragraph taken from the web site, physicsclassroom.com: It is often useful to think of these electrons as being attached to the atoms by springs. The electrons and their attached ...
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6answers
2k views

Why won't protons revolve around the nucleus containing electrons and neutrons?

In case of solar system,we can explain "Why Sun would not revolve around any other planet?",by giving the reason that Sun is heavier than any other planets. Heavier the body,greater will be the ...
3
votes
2answers
346 views

Hydrogen atom: potential well and orbit radii

I happened to open up an old solid-state electronics book by Sah, and in it he says: "it is evident that the electron orbit radius is half the well radius at the energy level En" The orbit radius is ...
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3answers
40 views

About the flow of current

Generally it is said that current is due to the flow of electrons; how can we make this claim? I mean, generally we say the atom contains a nucleus which consists protons (positively charged ...
1
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1answer
11 views

Will ionization energy be affected by screening effect?

It would be logical to think that the more electrons are ejected from an atom, the harder it is to eject more. I just learned about photoelectric effect experiment. The book is kinda telling me the ...
0
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1answer
34 views

If an atom emits a visible photon doesn't that mean it's visible?

A visible photon can be emitted and absorbed by an individual atom. Is this process sufficient for saying that we can see an individual atom with visible light? I realize the wavelength of visible ...
6
votes
5answers
581 views

What is the simplest possible experiment that proves that there are atoms? [duplicate]

As I known all the matter consists of atoms. What is the simplest possible experiment (with as little scientific equipment as possible) that can prove that there are atoms?
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2answers
52 views

Atoms In Space - More Specifically Helium [duplicate]

I've read several articles regarding the limited supply of helium gas on our planet and one that many scientists/engineers require for their research. I suppose if the government were to issue any ...
-4
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2answers
76 views

Would a piece of paper look as big as a small bedroom to an atom?, or bigger? [closed]

This evening my six year old asked me "Would a piece of paper look as big as this room to an atom?, or bigger?" ('this room' being a small sized bedroom) A friend suggested it would probably ...
1
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1answer
142 views

What is the most accurate experimental confirmation of Rutherford's $\sin^{-4}\phi/2$ law?

What is the most accurate experimental confirmation to date of Rutherford's $\sin^{-4}\phi/2$ law, where $\phi$ is the scattering angle?
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votes
1answer
208 views

How do I find the amount of atoms in a pure gas in a confined area?

Say I have Argon gas in an area such as a cube with pressure around pressure between 10-5 and 10-3 Torr (pressure) at 25 degrees at 320 Kelvins . How do I find the amount of atoms in that cube? Any ...
2
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2answers
116 views

Do atoms behave like waves? [duplicate]

I've heard someone state that the double slit experiment can also be done with atoms, not just electrons or photons of light.
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2answers
145 views

How many atoms are there in our solar system?

Including all objects gravitationally bound to the Sun, how many atoms are there in our solar system?
6
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3answers
2k views

Why do electrons in an atom 'fall' back to the ground state?

Why, after absorbing a photon does an atom's electron 'fall' back to its ground state (what causes it to immediately lose its absorbed energy)?
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2answers
40 views

Can high speed moving hydrogen atoms drive turbines?

We know that hydrogen is a part of air so if we accelerate hydrogen atoms in a circular vacuum tube as done in a particle accelerator, can the high speed moving atoms of hydrogen drive a turbine if we ...
8
votes
3answers
959 views

why dosen't a charged particle radiate energy in circular motion in a uniform magnetic field?

I have studied in my Physics course that one of the drawbacks of Rutherford's atomic model was that when an electron will revolve around the nucleus, it is undergoing acceleration and so it should ...
0
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1answer
54 views

Is it possible to decrease the mass of the object?

It is known that the Higgs boson gives mass to elementary particles. Also known that if manipulate with the Higgs field and decrease mass of particles then atoms starts to decay and the object will be ...
2
votes
4answers
162 views

How to explain what an electron is to someone new to physics? [closed]

I've got asked by someone who just graduated school and is about to start studying physics, what exactly is an electron, if it is not "a small ball rotating around the core of an atom". I couldn't ...
0
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1answer
50 views

How is the diameter of a nucleus measured? [duplicate]

From what i know, some statistical analysis is utilized in doing so. First, you take a thin slab of material, then fire particles which will reflect off the nuclei of the atoms in the material. The ...
0
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0answers
10 views

Atoms - deflection from the equilibrium state - oscillation [duplicate]

A homogeneous, spherical electron cloud describes an atom (radius $a_0$ and total charge $^−e $ and positive point charge$^+e$ as the nucleus. An external electric field stimulates the electron ...
0
votes
1answer
53 views

Estimate the amount of atoms in the smallest speck of matter you can see with the naked eye [closed]

I am currently working through a physics text book at my own pace on Newtonian mechanics. I came across this question in the the chapter 1 problems and had a bit of trouble with it. My biggest issue ...
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0answers
27 views

Collision between electrons & nucleus [duplicate]

I am new with physics and I have a confusion that since electron and nucleus has opposite charges then why they do not collide with each other inside an atom?
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0answers
30 views

What is the frequency associated to the orbitals within an atom?

I was told that there's a vibrational frequency associated to the orbitals within an atoms, but it is a frequency related not to a classical vibration. What Hz frequencies would these be?
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4answers
230 views

Does hidden variable quantum mechanics imply the collapse of atoms(electrons falling into the nucleus)?

why do atoms not collapse on themselves. Doesnt this problem rule hidden variables as invalid as the heisenburg uncertainty is the solution to the problem because it says electrons exist in a ...
57
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9answers
22k views

Why don't electrons crash into the nuclei they “orbit”?

I'm having trouble understanding the simple "planetary" model of the atom that I'm being taught in my basic chemistry course. In particular, I can't see how a negatively charged electron can stay ...
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votes
3answers
809 views

In truth, only atoms and the void

I have a question about this motto used by Sean Carroll in his blog: In truth, only atoms and the void. Can you explain what this sentence means? My interpretation is that the sentence does ...
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1answer
32 views

How does a high voltage produce ions

I was reading about gas discharge tubes and it said that when a high voltage is applied between the cathode and anode, electrons get pulled off the gas atoms. My question is how does this happen ...
0
votes
1answer
27 views

Reflection of light at a microscopic level [duplicate]

I always read that light is reflected by a mirror! My question is how does reflection takes place at microscopic level? Mirror is just atoms and electrons are revolving around the nucleus ! So where ...
0
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2answers
29 views

Why do the size of gaps/energy between different energy levels of mercury Hg vary as it goes further away from the mercury atom?

In hydrogen, the gap is getting increasing smaller, this is understandable: there will not be as much energy released as it goes down, and as attraction gets weaker. But in mercury the ordering is ...
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3answers
102 views

Elementary particles that make up an atom

How many real elementary particles (not hypothetical) make up an atom or can be in an atom?
1
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1answer
89 views

How much space does an atom occupy? [closed]

So my stupid question is: we know that in the classical model of a atom there is a nucleus at the middle and electron revolving around it in orbits numbered from 0 to infinity. So according to this an ...
0
votes
1answer
35 views

Does nucleus itself has its own motion?

We know that electron(s) is(are) moving around the nucleus, that consists of protons and neutrons. But does nucleus itself has its own motion, its own momentum, or the nucleus is stationary? Now, is ...
0
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0answers
27 views

Slope of p-orbitals at the nucleus

Is there any analytic expression describing the slope of the p-orbital at the nucleus, for example for hydrogen.
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2answers
95 views

Are there unobservable, undiscovered atoms?

Is it possible that there is a network of atomic activity that our current scientific instrumentation cannot detect? In other words, could it be possible that there are unobservable, undiscovered ...
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1answer
519 views

Why does mass in the universe have no limit in large size, but has a limit in small size?

We found VY Canis Majoris, a star so big it can't even be seen in scaled illustratations with the sun itself. However, we stop at particle physics, or quantum mechanics, i.e. particles, subatomic, ...
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1answer
60 views

Absorption from a classical to quantum

Today, I learned that using rubidium atoms at very low temperature in a Magneto-optical trap, one can experimentally show that the Lorentz classical derivation of absorption using dipole is valid. The ...
1
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1answer
38 views

Why only three combinations of three 1s-orbitals?

When bringing three $\mathrm{H}$-atoms close together, their 1s-orbitals will overlab and combine. I have a text saying that there are 3 ways to combine these. Those three combinations are: for ...
0
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1answer
72 views

Is there experimental evidence for the model of discrete intervals and orbital distances for electrons around the atomic nucleus?

Is there strong supporting evidence of discrete electron shells or orbitals surrounding atomic nuclei? I realize the math works out and we have energy frequencies emitted, perhaps even atomic ...
3
votes
1answer
85 views

What's in the empty space between a nucleus and the electrons? [duplicate]

I was thinking the other day about how the empty space in an atom is relatively huge, but I was wondering, is it really empty space? Originally I just assumed it was a vacuum and that was it, but that ...
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2answers
79 views

Are atoms compressible?

Liquids are not compressible, but what does compressible mean? Does it mean the increase in the density or decrease in volume? Or something else? Why are liquids incompressible, in a way nothing ...
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2answers
35 views

Molecules from atoms [closed]

Why does two oxygen atoms combine to form a molecule and not 3 or 4?Also why does one sodium and one chlorine atom combine to form NaCl while two chlorine atoms are required to combine with one ...
5
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2answers
211 views

If mesons were stable could they form atoms?

if there were stable enough mesons similar to protons and neutrons could they capture electrons to form exotic elements. if not why is this not possible?
0
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0answers
9 views

Velocity Selective Coherent Population Trapping and recoil limit on temperature

I have read that it is possible to go under recoil temperature limit using VSCPT (Velocity Selective Coherent Population Trapping) and that this method is based on atoms trapping in quantum state in ...
1
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1answer
50 views

photon absorption by atoms causes heat?

I have came up with a weird doubt: photon absorption by atoms causes heat? I mean, I was always told that if the photon's frequency is the magic one, the atoms absorbs the photon and goes to an ...
2
votes
1answer
40 views

Is it possible for two polarizable bodies to induce dipoles in each other in the absence of an external electric field?

If there exist two initially neutral bodies (say atoms) some distance apart, with no external electric field applied, can they induce dipoles within each other?
3
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3answers
2k views

If an atom is fully ionized by removing all electrons, is it still an atom?

This is a question about terminology. To me, it's clear that the nucleus of an atom is still an atom. But a comment by Willie Wong at Is nature symmetric between particles and antiparticles? raises ...
21
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3answers
3k views

Why isn't the color of a molecule a combination of the colors of its component atoms?

I was watching a documentary on youtube regarding Quantum Physics when it introduced the wavelengths of light emitted. Did a bit more research over the internet and I believe I understand the gist of ...
2
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1answer
137 views

If atoms are mostly empty space, why doesn't light pass through everything?

Atoms are mostly empty space, and although I now understand why matter doesn't pass through other matter, why don't photons pass through the empty space of the atoms? Is it the same sort of idea as ...