Questions tagged [atoms]
A nucleus made of protons and neutrons surrounded by a cloud of electrons equal in number to the protons.
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By recombination ion/electron does predominataly the ground level form?
When an electron is near an ion and has small velocity it will be certainly captured and both form an atom. I think that the electron will predominantly release energy dE just the proper quantity ...
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0answers
38 views
what is the cause of the first atom moving in moving?
I'm a computer student and I know nothing about physics and physics.stackexchange, so if I did something wrong, tell me to correct it (for example tagging). and ...
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2answers
57 views
What happens to the electron when a neutron knocks off a proton from hydrogen atom?
In recoil proton scintillators, the hydrogen acts as a neutron converter to produce protons when a neutron strikes a H atom. But what happens to the electron in H atom? Where does it go? Does it ...
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2answers
37 views
Why doesn’t the beta particle stay in the nucleus
When a neutron splits into a proton and an electron during beta decay, why does the electron fly out? Should it not stay close to the oppositely charged protons?
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1answer
45 views
How do you combine wavelengths of particles in an atom?
As the problem below results in the wavelength of a single electron, how would this combine/interact with other particles? In an atom, for example.
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0answers
24 views
Actual width of surface charge layer in conductors
In routine calculations we consider the width tending to zero and instead let volume charge density become a one-dimensional (radial) delta function.
Thinking classically in lieu of quantum reality, ...
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1answer
68 views
Empty space inside of atoms [duplicate]
Since most of the space between the nucleus and electron is empty space is that space in a vacuum?
I’ve not seen any info on this online or in textbooks does anyone have anything on this?
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2answers
75 views
What does the Heisenberg principle actually mean? [duplicate]
As far as I can understand, the Heisenberg principle limits the possibility of calculating the exact position and momentum of electrons, as the light we use to observe it changes it's velocity.
But ...
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0answers
15 views
Rutherford's and Bohr's model of atom [duplicate]
Rutherford's model of atom was ruled out because it failed in explaining stability of an atom. Since any particle that is accelerating continuously emit radiation. And in case of an atom eventually ...
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1answer
29 views
Two Dimensional Self-Reciprocal BravaisLattice
I've been reading Quantum States of Atoms Molecules and Solids by Morrison et al. for a condensed matter course. They make the claim that all 2D Bravais lattices are self-reciprocal, but I'm having ...
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1answer
41 views
Thomson's Plum Pudding and Rutherford's scattering [duplicate]
Why did Rutherford's scattering experiment disprove the plum pudding? Assuming a gold-atom to be a large homogeneous ball and hitting it with small homogenuous $\alpha$-balls should lead to the ...
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0answers
27 views
Why does the read-out efficiency increase when coupling an atomic ensemble to an optical cavity?
I went through a paper where it mentioned that the read-out efficiency of a quantum memory would be increased by coupling the atomic ensemble with an optical cavity.
I think rydberg atoms were used to ...
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2answers
45 views
Interpreting probability densities in atomic orbitals
I once read that an atomic orbital can be conceptualised as a cloud of "electron-ness". That is, the electron literally is the cloud, and the probability density only relates to the probability of the ...
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47 views
Why do atoms repel when they are very close to each other? [duplicate]
Why do atoms repel when they are very close to each other?
I know that this is not because of electrostatic force, but I do not know why atoms actually repel?
Our lecturer said that it arises from the ...
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1answer
69 views
Color of Every gas should be white?
The reason why halogens are coloured are because they absorb visible light and their electrons get excited to higher States this result in visibility of the complementary colour
But when an electron ...
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1answer
30 views
Why do we have more than one texture?
Say I rest my hand on a wooden desk. My hand does not go through the desk because my hand is made up of atoms and as is the desk. The atoms in my hand repel the atoms of the desk when I rest my hand ...
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1answer
36 views
Atomic shielding
Well the core of the atom has a positive net charge . For atoms with many electrons there is a negative electron cloud . How do valence electrons even exist? The electron cloud is closer to the ...
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3answers
83 views
Can an atom be split and put back together? [duplicate]
I had recent came across this question when unintentionally tearing a piece of my journal paper. These atoms' bonds are pulled apart when the paper is torn, but is there a way to put them back ...
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1answer
43 views
Experimental Assignment of Electronic Transitions in Atoms (Grotrian Diagram)
Grotrian diagrams often taught in instrumental methods of chemical analysis to chemists. After a decade, I finally found the original book of 1927 by Grotrian "Graphische Darstellung der Spektren von ...
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5answers
350 views
Does classical electromagnetism really predict the instability of atoms?
I will try to give a concise summary of what I wrote below. I understand that it is very long and apologize if I am wasting your time.
I used the Liénard-Wiechert potential and the Lorentz force ...
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1answer
84 views
Why atomic masses are quoted with reference to an isotope?
Is there any fundamental reason why atomic masses are quoted with respect to a certain element such as an arbitrary C-12 isotope whose mass has been set to 12 unit exactly? Previously, chemists have ...
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0answers
25 views
Is synchronized radiation possible?
Could it be possible to make 2 or more radioactive atoms, maybe plutonium, emit radiation at the same time? A kind of synchronized radiation. Perhaps this can be the basis for some kind of laser too.
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2answers
33 views
Rabi flopping vs. rate equation approach?
In Chapter 7 of C. J. Foot's Atomic Physics, Foot discusses the interaction of a two-level atom with radiation. He derives the phenomenon of Rabi flopping from the Schrodinger equation, using ...
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0answers
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Why does Magnesium burn hotter than other Group 2 elements?
It seems apparent, when one performs the standard "flame tests" in a lab, for the Group II elements that Magnesium burns by far the hottest and brightest. Why is this true?
I wouldn't expect this at ...
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0answers
29 views
What is the upper limit for the size of an atom? [duplicate]
I read an article saying an Israeli scientist had discovered the heaviest nucleus with 122 protons and 170 neutrons, and found it in a sample of purified thorium, and I would like to know if there are ...
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1answer
81 views
How much distance is there between electrons in an electron shell? [closed]
I imagine they would need keep a certain distance away from each other.
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1answer
59 views
What is the principal cause of diffraction?
I have found another question similar to mine here. But I want to know why does diffraction of light happen in the first place. I have found other resources on google which explain the topic partially ...
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0answers
21 views
Expectation value of coordinate mixed operator with ground state
I have a Hamiltonian of the Hydrogen atom:
$H=H_0+H_1+H_2$ , when: $H_0 $ is the hamiltonian from central force and from electron momentum , $H_1$ is the relativistic kinetic fixing, and $H_2$ is the ...
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2answers
50 views
Can we use a camera with a frame rate of 1 trillion FPS to observe electrons, protons, and neutrons?
Like with this camera from MIT that works at 1 trillion FPS: https://youtu.be/EtsXgODHMWk
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2answers
35 views
Energy change during electron transitions
I was studying Bohr's atomic model and came to know that when electrons make transitions in between the orbits they lose or gain energy in the form of electromagnetic radiations. I understand why they ...
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3answers
57 views
formation of atomic nuclei from nucleons
What holds the nucleus together? In a nucleus there are several
protons, all of which are positive. Why don't they push themselves
apart? It turns out that in nuclei there are, in addition to
...
1
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1answer
82 views
Where does the momentum go when atom absorb a photon? [duplicate]
Imagine an electron around an atom absorbs a photon and becomes excited, it has now jumped to a higher orbital. At this point in time, where does the momentum of the photon goes?
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1answer
96 views
Whether this proof regarding Bohr's second postulate is true or false?
Let us assume a particle oscillating with displacement $x$.
Now $x = A\sin(2πft)$
$$\frac{\mathrm d x}{\mathrm dt} = v = 2πfA\cos(2πft)$$
Now $KE_\text{max}$ can be given when cosine value is 1; ...
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2answers
28 views
Variation of electronic energy levels $E_{nl}$ of a many-electron with $n$ and $l$
Within the central field approximation, the electronic energy levels $E_{nl}$ depend on both $n$ and $l$.
For a given value of $n$, $E_{nl}$ increases with increasing value of
$l$.
For a given ...
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7answers
4k views
How does Brownian motion prove the existence of atoms?
I have heard many people say that the existence of atoms is proven by Brownian motion. Now, I understand how an atomic theory would suggest the existence of Brownian motion. However, who is to say ...
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0answers
39 views
How can Coulomb's Law work in derivation of atomic radius? [duplicate]
Coulomb's Law for the force between two charges do not work for moving charges. For a single electronic atom, the electron moves around the nucleus. But in deriving the formula for finding an atom's ...
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2answers
49 views
Rutherford gold experiment
When an alpha particle is nearing the gold atoms nucleus, it is slowing down due to electrostatic repulsion, right?
But then why is the acceleration or velocity not a minimum at that point (the ...
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2answers
38 views
What is the relation between difraction and energy levels?
Imagine I have an atom in the cold space. The energy gap between its current energy and the next is exactly equals to the photons energy that is about to meet an atom. Atom absorbs photon. All is fine,...
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2answers
84 views
Entanglement in atoms, nuclei and quantized fields
Are the particles that are bounded by chemical bonds or nuclei joined by nuclear forces entangled or are they pure states?
In addition to that, are the subatomic particles in the atoms and nuclei, ...
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2answers
88 views
Can we show that the ground state of the He atom is a spin singlet rather than triplet?
The ground state of Helium atom is a state in which the space part of the wavefunction is symmetric and the spin part is antisymmetric under the exchange of the electrons. Therefore, the ground state ...
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0answers
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How to estimate the mobility of atoms implanted in the interstitials and/or vacancies of a crystal?
I would like to compare the likelihood for implanted helium atoms to move from interstitials/vacancies of a crystal versus neon atoms. I read in the literature that He atoms located in interstitials/...
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2answers
77 views
How can high voltage create ions?
So I was reading about Tesla Coil propulsion and Ion Thrusters.
The thing I don't understand is the following:
As it is shown on the image, when an electron colides into a gas atom, it ionizes it. ...
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4answers
245 views
How do orbitals exist in an atom?
I have come across a picture online which talks about 1s,2s,2p orbitals of a sodium atom.
Observation:In the picture we see some volume of space in common to two orbitals.
For example:The circled(...
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2answers
62 views
Electron movement in 3d Bohr model
During a thought experiment, I observed that I was not able to figure the Bohr model in 3d.
In every picture I saw up to today, the electrons orbit the nucleus on a fixed circle-like path.
But while ...
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2answers
107 views
Is there a link between nuclear radiation and sound? [closed]
I'd like to understand if it's possible to relate/imagine a link or relationship between nuclear radiation and sound. A simple description would be appreciated since I don't have a deep understanding ...
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1answer
66 views
How can an ion ever capture an electron if an electron requires a precise momentum to match a subsequent orbital?
Suppose an electron approaches a proton with greater energy than the hydrogen ground state. Will the electron scatter? If so, how could an electron ever be captured given it would require exactly the ...
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1answer
68 views
If you were to be crossed by a wire the width of a single atom, would you still be split in half? [duplicate]
Supposing it is solid and wouldn't snap or break. Would it guillotine you or just pass through leaving you unwounded?
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1answer
58 views
Why ferromagnetism requires exactly 2 electrons in the last orbit?
All magnetic materials like iron, cobalt etc.. have 2 electrons at the last orbit. But magnetic field occurs even if a single charge moves. Why exactly 2?
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1answer
178 views
Why don’t electrons fall into the nucleus of an atom? [duplicate]
The nuclei of atoms are composed of protons and neutrons. The proton has a positive charge, and the neutron a neutral charge. Shells of electrons outside the nucleus in the atom orbit around the ...
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4answers
13k views
If an apple is magnified to the size of the earth, then the atoms in the apple are approximately the size of the original apple
Quoting from the Feynman Lectures on Physics - Vol I:
The atoms are 1 or $2 \times 10^{−8}\ \rm cm$ in radius. Now $10^{−8}\ \rm cm$ is called an angstrom (just as another name), so we say they are ...
