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

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Is an electron/proton gun possible?

In the 1944 SF story “Off the Beam” by George O. Smith, an electron gun is constructed along the length of a spaceship. In order to avoid being constrained by a net charge imbalance, it is built to ...
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1answer
923 views

Radial Schrödinger equation

I found a problem that says: Show by direct substitution that $R_{10}$ is a solution of Schrödinger's radial equation. AFAIK Schrödinger's radial equation is ...
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1answer
168 views

How much lead is there in the universe?

I know there is around 10^80 atoms in the observable universe, but is there any estimate the amount of lead in the universe (within a couple magnitudes of 10)?
3
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1answer
409 views

What are independent parameters in Hellmann–Feynman theorem?

A typical example in textbooks about the application of Hellmann–Feynman theorem is calculating $\left\langle\frac{1}{r^2}\right\rangle$ in hydrogen-like atoms. Wikipedia has a nice demonstration of ...
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2answers
6k views

Comparing scales of atomic level objects to scales of everyday size objects

I am trying to come up with everyday size objects comparisions of atomic scales items, e.g. if a proton probability cloud was of size basketball how far would the next atoms to it be? reason being is ...
8
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1answer
378 views

Why atomic bomb makes a mushroom?

Atomic bombs make mushroom. It's well-known and we've seen many images of atomic experiments around the world. My question is, why mushroom? Does TNT and Grenade also make mini-mushrooms? Is it a ...
18
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3answers
2k views

What really cause light/photons to appear slower in media?

I know that if we solve the maxwell equation, we will end up with the phase velocity of light is related to the permeability and the permittivity of the material. But this is not what I'm interested ...
2
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3answers
846 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 ...
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1answer
398 views

Why can free lithium atoms not take part in an Auger process?

Shouldn't it be possible for an incoming photon to excite one of the 1s electrons to a 2p state (or one of even higher energy) and then for the excited electron to drop back to 1s and kick out the 2s ...
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2answers
344 views

Why and how, in QED, can excited atoms emit photons?

The quantum mechanics of the structure of atoms as determined by the electromagnetic forces inside them correctly describes the location and coupling of the different energy levels in essentially all ...
6
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1answer
704 views

Is Palladium an exception?

I have been taught in school that atoms cannot have more than 8 electrons in the outer shell. Palladium atom's electron configuration is 2,8,18,18. Why isn't it 2,8,18,17,1 like the case of Platinum ...
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4answers
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Atomic mass of Copper-63?

This URL lists the mass of Copper-63 as 62.9295975(6) and this other URL lists the mass as 62.939598. These values differ by almost exactly 0.01 which seems hard to explain by experimental error. ...
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2answers
394 views

Electrical neutrality of atoms

How is it that atoms with equal numbers of protons and electrons are described as "electrically neutral" when the proton is 1,800 times more massive than the electron?
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5answers
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Is there the smallest particle that can be guaranteed to be unable to be broken down into smaller particles?

Is there the smallest particle that can be guaranteed to be unable to be broken down into smaller particles?
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1answer
689 views

Open shells in Quantum mechanics of multielectron atoms

This question: How do electron configuration microstates map to term symbols? And the discussion of multielectron effects here: Quantum Computing and Animal Navigation Inspired me to try to understand ...
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3answers
340 views

Is it possible to bind an entangled electron to the outer shell of an atom or just a proton?

Say we start with an entangled electron--positron pair and we separate them. I want to take the entangled electron and bind it to a proton or the outer shell of an atom. Is it possible to do this ...
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3answers
3k views

Photon hitting an atom with higher energy than needed to ionize

Suppose we have an atom with several energy levels (e.g. an hydrogen), and it is hit by photons. I know that in order to have the atom change energy levels, the photon must have an energy level ...
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2answers
17k views

What is in the space between a nucleus of an atom and its electrons?

There is a common analogy about the structure of an atom, such as the nucleus is a fly in the centre of a sports stadium and the electrons are tiny tiny gnats circling the stadium (tip of the hat to ...
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4answers
1k views

Why does amount of protons define how matter is?

My question might sound convoluted but my mind is twisting right now so my apologies in advanced. Why is it that when I have one proton and one electron it is Hydrogen a clear flammable gas, and ...
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1answer
555 views

Scaled energy output of a hydrogen atom

I'm trying to get a grasp of the power within a single hydrogen atom (e.g. the power released when whatever process happens in a hydrogen bomb)... If we could enlarge a hydrogen atom up to the size of ...
3
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2answers
2k views

How does electron excitation relate to atomic orbitals?

Taking off from the Rutherford-Bohr model, Figure 1. Rutherford-Bohr model. when an electron absorbs energy (from light, heat, or otherwise) it jumps to a higher energy level, or shell. Then when ...
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3answers
8k views

Why is the relationship between atomic number and density not linear?

What are the factors that affect the density of an atom?
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1answer
139 views

Effect of Cosmological Expansion at the Atomic Level [duplicate]

Possible Duplicate: Why does space expansion not expand matter? Does cosmological expansion have any effects at the atomic level?
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2answers
4k views

Zero probability of finding an electron in the nucleus

One and the same electron in a p orbital and taking part in a common π (pi) bond has two lobes visualized as connecting through the nucleus. There is however zero probability of finding an electron at ...
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2answers
4k views

How does electron move around nucleus?

I need to get a nice picture about how electron moves around nucleus? I find concept of probability and orbitals quite difficult to understand?
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2answers
78 views

Is there a [set of] rules/patterns that apply to elements [duplicate]

Possible Duplicate: Do current models of particle physics explain the chemical properties of elements/compounds? Is there a rule/pattern, or multiple rules and/or patterns, which describe ...
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6answers
4k views

Why does space expansion not expand matter?

REFORMULATED: I have looked at the other questions (ie "why does space expansion affect matter") but can't find the answer I am looking for. My question: There is always mention of space expanding ...
14
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1answer
986 views

Turned to steel in the great magnetic field

This is obviously a "fun" question, but I'm sure it still has valid physics in it, so bear with me. How great of a magnetic field would you need to transmute other elements into iron/nickel, if ...
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5answers
3k views

Which experiments prove atomic theory?

Which experiments prove atomic theory? Sub-atomic theories: atoms have: nuclei; electrons; protons; and neutrons. That the number of electrons atoms have determines their relationship with other ...
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2answers
1k views

Appearance of atoms

I was watching a documentary entitled "The Atom" and one of the statements made was that Atoms behave differently when we look at them. I wasn't too sure about the reasoning behind this and i'm hoping ...