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

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109 views

What is the pressure of a gas required to ionize the gas using an electron gun?

How dense does a gas (Argon in particular ) have to be to in order to ionize it using electron bombardment and weak magnetic fields. Is there a correlation with the density of a gas and the easiness ...
4
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1answer
331 views

Do inner shell electrons feel the electric field/force from an outer shell electron in an atom?

We just finished studying Gauss’ law and were puzzled by this thought. If I look at a copper atom and focus on the 29th electron in the 4th shell, according to Gauss’ law, I can draw a Gaussian ...
2
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2answers
338 views

Why do smaller objects become harder to break?

When grabbing a typical tree branch of at least two feet, it's so easy to snap with a less than one inch circumference that even a toddler can do it. However, after breaking it, the smaller halves ...
2
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1answer
90 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 ...
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1answer
161 views

Term symbol - how do we know the number of electrons $e^-$?

Lets say I have a term symbol $^4D_{5/2}$. From this I can simply read the total quantum numbers numbers $L=2$ and $J=5/2$. Now the superscripted number $4$ is called multiplicity if I am not ...
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2answers
201 views

LS Coupling - weird image in the book

In the book by Arthur Beiser, Concepts of modern physics, in the chapter LS coupling there is this image: QUESTION: How do we get total orbital angular momentum $L=3$ (image (a)) out of quantum ...
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1answer
439 views

Total angular momentum - single electron

I have been dealing with total angular momentum of the single electron which is outside the closed shells in which sum of the angular momentums is zero. My book says that total atomic angular ...
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3answers
186 views

Could I use an electron gun to make plasma?

Could I ionize a gas using an electron gun and knock off electrons in the gas to make plasma?
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0answers
43 views

How do you determine the energy of an isotope?

How do you determine the energy of an isotope? I there a calculation for it? Sorry for the confusion
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1answer
99 views

Evidence of atoms from Dulong–Petit law?

All materials have same molar specific heat, cf. the Dulong–Petit law. Is it an evidence of atoms? What other examples are there for atomic theory?
4
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1answer
305 views

Atoms: boson or fermion? [duplicate]

The spin of fundamental particles determines if they are bosons or fermions. The atoms also have bosonic or fermionic behavior, for example $\require{mhchem}\ce{^4He}$ has bosonic and $\ce{^3He}$ has ...
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3answers
789 views

What is the quantum mechanical explanation of the octet rule?

What is the quantum mechanical explanation of the octet rule? In other words, what makes the octet rule be true from a quantum mechanical view? How we explain what makes some atoms don't follow the ...
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2answers
138 views

Can I excite an already unstable element for accelerated decay?

Say I had an unstable element ready to go through beta decay and I introduced it to high speed electrons: would this lessen the time needed for the product to go through beta decay?
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1answer
76 views

Can radioactive isotopes stay unstable after beta decay?

Say you had a very radioactive element in a confined area: could that element (hypothetically speaking) go through beta decay, then, once it has too many protons could it immediately go through ...
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1answer
68 views

Is the “pressure” as we know a kind of “instantaneous action at a distance”?

This may be a very simple question, but I still dont know how that work in the essence (quantic/atomic level) Consider the image bellow: How the "pressure (air atoms) " known that in the other ...
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1answer
105 views

Storing kinetic energy in bonds

Let's assume a setup with a static linear molecule with three identical atoms connected by bonds and a single atom, identical to the other three, being shot at the molecule. Let's also assume that ...
17
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4answers
554 views

Is the electromagnetic spectrum discrete?

I'm just starting to learn physics and I have a question (that is probably stupid.) I learned that energy levels that the bound electron can have are discrete. I also learned that when an electron ...
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1answer
69 views

Difference between photo electron spectrum and photoelectron angular distribution

I am trying to learn the Photoelectron velocity map imaging. While I was going through the article "Chem. Soc. Rev., 2009,38,2169-2177", it is said that the "photoelectron spectrum reflects the energy ...
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1answer
173 views

On the atomic level, how is incandescent light structured?

I want to know from the smallest possible originating structures how the light I see generated from heat is made by atoms themselves.
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1answer
105 views

An electron emits a photon and the core is pushed (recoiled) back!

I have come across a problem which is a homework indeed, but i tried to pack this question up so that it is more theoretical. What I want to know is: If I am allowed to write energy conservation for ...
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2answers
140 views

Weird definition of Bohr radius on Wiki

On the Wikipedia I found that the Bohr radius is equal to: \begin{align} \boxed{r_b=\dfrac{4\pi\varepsilon_0\hbar^2}{m_e{e}^2}} \end{align} but while we have been learning Bohr's model we derived ...
3
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1answer
307 views

Why electron clouds in atoms don't radiate? [duplicate]

I was reading that Bohr assumed electrons in orbit simply did not radiate, and my professor told me that the actual case is that electrons are clouds of probability. Even so, aren't they still moving ...
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2answers
155 views

classical understanding of an atom [duplicate]

A problem in Bohr's day was understanding why an orbiting electron does not continuously radiate an EM field. An orbiting electron is a moving charge and according to Maxwell, this should generate an ...
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1answer
1k views

What is heat and how does it effect an atom?

What happens in the atom when it gets heated or cooled and turns into gas, liquid or solid? I just want to know how does heat affect an atom.
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1answer
488 views

Alpha decay, why does it occur? [duplicate]

I was reading about alpha decay and why it happens. The strong force holds protons and neutrons together, but I don't get why does an atom emit helium nucleus when it has too many ...
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0answers
64 views

What is the physical property of metal nanoparticles?

I am a Math student but now I have to deal with gold nanoparticles in aqueous solution. Now I was wondering whether the physical properties of gold nanoparticles are the same as the properties of gold ...
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1answer
99 views

How does adding electrons break the angular momentum degeneracy?

In the hydrogen atom, the energy does not depend on l. This degeneracy is sometimes called "accidental" (because it does not correspond to some symmetry?). However, there is l dependence in the energy ...
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1answer
503 views

Why an electron “rotate” around the nucleus at a speed close to the light one? [closed]

Why an electron "rotate" around the nucleus at a speed close to the light one? I mean where he gets all this energy? One DOES NOT simply approach the speed of light AFAIK.
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1answer
228 views

home made atom destruction unit [closed]

Today we learnt at school that atoms can be destructed. I believe Physics is a great science to do experiment and I would like to try it at home. Could you tell me what I need to do it? and is it ...
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1answer
224 views

Atomic gravitational field?

This might be a silly question, but if every atom has its own gravitational force could atoms or molecules be attracted to each other over vast distances in the void of space if there were no other ...
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1answer
205 views

How to determine the region that would contain a quantum particle

(a) A hydrogen atom is in its ground state. If space is divided into identical infinitesimal cubes, in which cube is the electron most likely to be found? If instead space is divided into 31 ...
2
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1answer
96 views

Could one “build” elements?

I was wondering this: would it be possible to "construct" elements by arranging their constituent particles in high-energy environments? So apart from just fusion, could you sub-atomically manufacture ...
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0answers
109 views

Total angular momentum in multielectron atoms

I have some confusion about orbitals in multielectron atoms. Let's say we consider an atom (Lithium, for example, $1s^2\, 2p^1$) and that the state of the last electron is [n=2, l=1, ml=0, s=1/2, ...
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1answer
378 views

How can we describe the electrons of multi-electron atoms (i.e. not Hydrogen) when equations/analytic solutions only exist for Hydrogen?

I've been digging into emission spectra of different elements and found that such things as the Rydberg equation, Bohr's model, and quantum mechanics can only fully describe the single electron in the ...
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11answers
2k views

Where did Schrödinger solve the radiating problem of Bohr's model?

One of the problems with Bohr's theory to describe the hydrogen atom, was that the electron orbiting around the nucleus has an acceleration. Therefore it radiates and loses energy, until it would ...
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1answer
1k views

Energy required for ionizing Helium

The energy required to remove both electrons from the helium atom in its ground state is 79.0 eV. How much energy is required to ionize helium (i.e., to remove one electron)? ...
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2answers
125 views

How does one subtract two light beams?

From what I understand, it seems like you can only "add" beams together. You can use a beam combiner, basically using a beam splitter in reverse, to combine two beams. In homodyne detection, you use a ...
2
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1answer
570 views

Dark and bright areas around atoms in a scanning tunnelling microscope image

Recently IBM created world’s smallest ever animation on an atomic scale video. Researchers made the animation using a scanning tunnelling microscope to move thousands of carbon monoxide molecules to ...
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1answer
405 views

Difference between atom and elementary particle questioned

Hydrogen ion doesn't have one electron which clearly mean that it has only one proton..So hydrogen ion is only a proton. Am I right, please make it clear. If hydrogen ion and proton are same that how ...
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1answer
103 views

Atoms in our body

Our body of course exchanges some atoms with environment every day however are there some of atoms which stay with us a life time?
3
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1answer
147 views

How fast did hydrogen atoms travel when they were first formed in the early universe?

I can't seem to find any data on this, is it a known value?
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0answers
36 views

Electron Configuration and Binding [closed]

Boron with an electron configuration of $1s^22s^22p^1$ has an atomic weight of $10.811u$. What is the total binding energy for 11Bs if $Mn = 1.008665u$ and $Mp = 1.007825u$. I cannot find anything ...
6
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3answers
628 views

Graphene +1 extra carbon bond

I'm not a physicist just a curious mind, so please go easy! I was just watching a BBC Horizon Documentary that featured a piece on the recently discovered material Graphene. One of the facts ...
2
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1answer
45 views

Minimum atomic clearance permitting motion

Suppose you were to build the piston and cylinder in a car engine atom-by-atom. Let's just say carbon, since you can make a lot of different shapes due to it's high valence. So assuming you make the ...
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1answer
539 views

What is longitudinal relaxation time and transverse relaxation time? [closed]

How do we define the longitudinal relaxation time and transverse relaxation time?
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1answer
2k views

How electrons act under rotating magnetic field?

I study Power Engineering in University. Today I asked my lecturer to explain me exactly how atom's electrons act under spinning rotor's magnetic field, that generated dynamic electricity. But he even ...
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0answers
121 views

How large must the Quantum teleportation fidelity have to be in order for it to be useful?

This question relates and stems from my original question. Please read this one and the comments before answering this question. Quantum Teleportation Fidelity I know that for discrete variables ...
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1answer
2k views

Why is carbon dating limit only 40,000 years?

For an example, when they tried to get the carbon dating for presence of Aboriginal people in Australia they get to the number 40,000. But it could be much earlier. Why is that 40,000 years limit for ...
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2answers
229 views

Why is electron presented in books, pictures as a sphere?

Why is electron presented in books, pictures as a sphere, when in fact it's not?
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2answers
3k views

The number of degrees of freedom of a monatomic gas

Suppose that I have a monatomic gas sample consisting of $N$ atoms (e.g., $N$ argon atoms); thus there are no vibrations or rotations. How many degrees of freedom does the system have? Does the ...