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

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Is it possible to view an atom? [duplicate]

Is it possible to view an atom? What would it look like? Would it resemble a traditional atomic diagram?
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113 views

Why doesn't silicon emit light? [closed]

Why doesn't silicon re-emit light when light falls on it? Or if it emits light then why we can't see it?Hence it has valence electrons.
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1answer
31 views

Gasses and Gravity

I have two questions. First question. When gas is placed inside a container it fills the container evenly with constant pressure. If the container size varies the gas expands or is compressed but the ...
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2answers
2k views

J.J. Thomson's cathode ray tube: Why does the magnetic field bend the cathode ray downward?

The cathode ray is bent upward toward the plate by electric field and downward by the magnetic field. The first part isn't what I am confused about. However, the second part is. How did the ...
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1answer
42 views

Why insulators do not conduct electicity when they are negatively charged?

The following excerpt is from Young and Freedman 13th edition: Most metals are good conductors, while most nonmetals are insulators. Within a solid metal such as copper, one or more outer ...
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3answers
61 views

Are atoms elementary? [closed]

I'm reading wikipedia about Real neutral particle. I know, there are many different particles discovered in the background of atom, which was ( Neutrons + Protons + Electrons ) before. For example, ...
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186 views

What does an orbital mean in atoms with multiple electrons? What do the orbitals of Helium look like?

I am wondering about this. It is a familiar sight, the orbital diagrams for the hydrogen atom, depictions of which are abundant and so are not in need of reproduction here. However, what about the ...
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2answers
116 views

Does the attached figure show how particles produce wave?

I have always been trying to understand and visualize what wave is and how it's been produced. I guess what ordinary people know about wave is just a particle moving up and down but last week I came ...
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1answer
34 views

What is the reason behind the very high value of nuclear density? [closed]

I know how to arrive at the formula but I want to know it's such a huge number almost 2 X 1017 kg m-3, which is a huge number, all the more surprising to me is that it's a constant! Each and every ...
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1answer
45 views

Can you see Bose-Einstein condensates with the naked eye?

In this article it is said that "A BEC is a group of a few million atoms that merge to make a single matter-wave about a millimeter or so across." Does this mean that when they make a matter wave ...
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1answer
50 views

Does the proton wobble due to the electron's orbit in a Hydrogen atom?

In a hydrogen atom the nucleus only has one proton and no neutrons so the electron to nucleus radio is higher for hydrogen than that for any other atom. Does the orbiting electron induce a wobble on ...
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64 views

How does heat damage the body? [closed]

Let's take an example : If I put my hand in cold water (let's say 20°C), it doesn't hurt, and it doesn't burn. But if I put my hand in hot water (let's say 90°C), it hurts and my hand can get burnt. ...
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46 views

What is the largest distance for which the influence of the electric field of a single electron was measured?

I suppose that Rydberg atoms are the best way to find by experiments the largest distance of influence of the electric field of a single electron in a electric dipole. Furthermore how the electrical ...
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0answers
18 views

do gravity shows its effect in atomic level? [duplicate]

how much of a effect do gravity shown in atomic level. how significant or negligible is it. i am guessing the effect is small because the mass of nucleus and electron is small. But the distance ...
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2answers
292 views

Can you breakdown an atom?

Protons, neutrons, and electrons make up the atom, but I've heard that you can't breakdown an atom. How do we know that the electrons, protons, and neutrons make up the atom without being able to ...
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1answer
54 views

The force applied by two charges on each other when there is another charge nearby them

QUESTION 1 Let me give two simple scene of charged particles to make you understand my question. There is a fixed positive charged particle in the center. Scenerio 1 : A fixed negative charged ...
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1answer
106 views

How is magnetic field created in an atom according to quantum model

How is magnetic field created in an atom according to quantum model? I mean, we are taught about the magnetic field by bohr's model which assumes that electron revolves around the nucleus in a ...
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3answers
65 views

Splitting molecule

The photon reacts with the binding electrons orbiting the two atoms. The photons have the 'correct' wavelength for Bond Dissociation Energy (BDE). 'Splitting' the molecule involves applying the ...
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4answers
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How to determine what an object is composed of?

Heads up: This question has never been asked (here) before the way I will ask it here, so let's shed some light on it a bit. Prelude and anecdote(can be skipped): The other day I was walking home, ...
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1answer
72 views

Can we touch the atoms? [duplicate]

This question is basically a spin off from my friend's question - "What are we basically seeing? Is it the atom or the nucleus?" (He had referred to the huge amount of empty space inside the atoms). I ...
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1answer
32 views

When light is reflected, if some of the light is absorbed in the particle, does it change the particle?

Which color/frequency of the light is absorbed and which part is reflected? How is it determined which part will be absorbed? Does that depend on the particle? N.B: When I say particle, please keep ...
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1answer
44 views

Deexcitation times for ytterbium

I need to find the deexcitation times for the transitions found in Figure 1 of Nature Phys. 8, 649 (2012), arXiv:1206.4507. That is, what is the deexcitation time for the following transitions: $$ ...
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3answers
97 views

Why do electrons have to fall on the nucleus in the Rutherford atomic model?

As I read on Wikipedia, the Rutherford atomic model is not correct according to classical electrodynamics, as it states that electron must radiate electromagnetic waves, lose energy and fall onto the ...
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1answer
47 views

Struggling with a conversion. Showing number of atoms per cubic meter using pressure in Torr

I have been trying to show that the following is true: N = 9.65 x 10^24 x (P/T) Where N is the number of atoms per cubic meter of an ideal gas at pressure P (in Torr) and temperature T (in Kelvin). ...
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0answers
55 views

How much of the Solar convection zone is completely ionized?

I was reading about the energy transportation in stars here, and I found this: "The outer portion of solar mass stars is cool enough that hydrogen is neutral and thus opaque to ultraviolet photons, so ...
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3answers
5k views

Difference between spin-orbit coupling and LS coupling (Russell-Saunders)

I'm having some trouble understand what the difference is between these two. It seems as though there are kind of the same, but that spin-orbit coupling reduces to LS coupling under certain ...
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40 views

How does positronium work?

I've heard that in positronium, electrons and positrons orbit each other before annihilating one another shortly after. However, I thought that electrons never orbit anything, but instead have a ...
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12 views

Can the atomic vibration of molten liquids be decomposed into a superposition of a series of normal modes?

From what I've learned, molten liquids have short-range periodicity (short-range doesn't just apply to the amorphous solid state/glassy state). So does this mean that, along with amorphous solids, the ...
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2answers
311 views

Atomic natural line width

In laser cooling, with a model of a 2-level atomic system, spontaneous emission is stated to be dependent on the "natural line width" of the excited state of the atom. This width is defined as the ...
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2answers
123 views

diffusion velocity

i understand that diffusion is the movement of particles from high concentration areas to low concentration, but what is the cause of that movement atomically. And especially in the case of charge ...
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2answers
148 views

Could I turn into a nuclear bomb?

Just out of curiousity, could the nuclei of our atoms split via quantum tunnelling, thereby leading to nuclear reactions and ultimately turning us into atomic bombs? I know that this is ...
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2answers
119 views

How massive can an atom get?

After reading this thread, it appears to me that creating a new element is a game of chance some sort of an art. It also appeared to me that the higher you go, the harder it is to make an element. ...
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2answers
468 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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1answer
45 views

In a lattice, what, technically, are random (thermal) atomic motions?

I'm familiar with normal modes and their periodic nature. And I know that the term 'independent mode' is used to describe how each individual atom in a lattice can move (degrees of freedom). But, ...
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1answer
30 views

How would an eruption affect radiocarbon dating?

Nuclear testing above ground and the burning of fossil fuels might affect the outcome of radiocarbon dating. How would an eruption the size of Yellowstone or larger affect radiocarbon dating?
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2answers
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What exists in the Space between quarks

Apologies to all if this has been asked before, I searched but was unable to find one similar. This is a question that has been bugging me for a while that i haven't really been able to find a ...
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3answers
4k views

What does a subatomic charge actually mean?

I was recently reading a popular science book called The Canon - The Beautiful Basics of Science by Natalie Angier, and it talks about subatomic particles like protons, neutrons and electrons in ...
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2answers
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When an atom emits a photon are all directions equally likely?

When an atom has an electron in an excited energy level and it transitions to a lower level it emits a photon. What direction is it likely to emit the photon in? Are all directions equally likely, ...
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1answer
165 views

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

What is the most accurate experimental confirmation to date of Rutherford's $\sin^{-4}\frac{\phi}{2}$ law, where $\phi$ is the scattering angle?
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4answers
871 views

Why does optical pumping of Rubidium require presence of magnetic field?

The optical pumping experiment of Rubidium requires the presence of magnetic field, but I don't understand why. The basic principle of pumping is that the selection rule forbids transition from ...
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4answers
4k 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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6answers
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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 ...
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3answers
46 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 ...
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1answer
42 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 ...
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1answer
44 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 ...
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5answers
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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
72 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 ...
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2answers
109 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 ...
2
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1answer
364 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 ...