Smallest particle still characterizing a chemical element. It consists of a nucleus of a positive charge, carrying almost all its mass and electrons determining its size. This tag should be applied to questions that specifically concern these particles and their properties.

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How do scientists count the exact number of electrons, protons, neutrons in the atom?

An atom is very small so it is probably difficult to focus exactly on a single atom. I wonder how scientists count the exact number of electrons, protons, neutrons in an atom of a certain element. ...
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31 views

Alpha and proton repulsion [on hold]

Why alpha particle get repelled when came in contact to nucleus even though alpha particle has more mass then proton?
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Why don't electrons just crash into the nuclueus? [closed]

This question has already an answer on Physics.SE: Why don't electrons crash into the nuclei they “orbit”? I've seen some answers to this questions on google, but they don't go into really ...
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35 views

Is there a way to alter the electron could density of atoms? [closed]

Do we have any method to dynamically alter the properties of the electron could density of atoms? Let's consider atoms as a ball with electron could density around them. Is there a way to apply a ...
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1answer
181 views

Are photons ejected from atomic nuclei?

I have heard that electrons absorb or eject photons when transitioning from one orbital to another. Is this correct? Can atomic nuclei eject photons?
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How would I find an apporpriate dopant element for a lattice

I am trying to figure how would I go about finding a dopant element that would fit in a copper lattice? I already have the data for the atomic dimensions and structure (available below), however how ...
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34 views

Periodic Trends of Zeff and Electronegativity

The effective nuclear charge $Z_\mathrm{eff}$ increases from left to right and from top to bottom. Can you explain why it increases from top to bottom? Also can we explain the periodic trend of ...
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31 views

Electron's Energy In The Atom

I know that the exact (OK most of the times not the exact) energy of an electron can be calculated by solving Schrodinger's differential equation, but can we explain an electron's energy of a specific ...
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32 views

Confused about writing out electron configurations

I watched the Crash Course chemistry video about the electron. In the video Hank showed an example configuration of iron as $\mathrm{(1s)^2 (2s)^2 (2p)^6 (3s)^2 (3p)^6 (4s)^2 (3d)^6}$ and explained ...
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Few basic questions about ionic bonding and batteries (lead)

I've got a few very very basic questions about ionic bonds and their role in batteries. My assumptions (correct me if I'm wrong): Ionic bonds occur between a metal and a non-metal (the non-metal ...
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2answers
79 views

Does Bohr's theory violate the Uncertainty Principle?

In a book, it is stated that one reason for the failure of Bohr's theory was the fact that it violates the Uncertainty Principle. Is this fact true? if so, explain to me how it violates the ...
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21 views

What determines the color of a object? [duplicate]

Why is gold yellow for example? Which property of the atom determines the color?
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How do I visualize an atom?

I have searched and searched, oh how I have searched. I am looking for a 3-dimensional visualization of a whole (i.e., moderately complex) atom that includes orbital geometry. A proper "layered" view ...
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1answer
55 views

The proper explanation for the general formula of the DU? [duplicate]

I found a formula for the degree of unsaturation (DU) in Clayden’s Organic Chemistry. It explains, simply, the unsaturation with the difference in H atoms. Then I stumbled upon the general formula: ...
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20 views

Do we have a reasonable assurance that relative atomic mass is constant throughout the universe? [duplicate]

I know atomic mass can be (over) simplified as the average mass of all isotopes of a given element weighted by the ratio of their natural occurrence. I also know that, as far as we know, refining ...
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1answer
450 views

How does sulphur has atomicity 8 [duplicate]

How does sulphur has atomicity 8, when its valence electrons are 6 like oxygen- ie even 2 sulphur atoms can share a pair of electorns and acheive the octet rule,why it should involve 8 atoms
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Question about quantum mechanical model of atom and the quantum numbers

I studied Bohr's model of atom and then the drawbacks of it and then quantum mechanical model of atom. Now quantum model is according to uncertainty principal and dual nature of matter and it says we ...
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1answer
30 views

Can atomic number change the type of electromagnetic radiation being emitted when a electron drop from a energy level to another?

Without getting into too much/any math, I just wanna talk about intuitions if possible. If atomic increase, the attraction increase, and consequently the potential energy increase. More energy leads ...
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122 views

Which elements can be diatomic?

Which elements can be diatomic and why? Motivation I shall discount the noble gases as they do not usually form bonds anyway. Looking at the non-metals. See below. Hydrogen, Nitrogen, Oxygen and ...
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1answer
59 views

Is it possible to have a diatomic molecule of sodium in gaseous state?

Already I know that hydrogen, all the halogens, nitrogen and oxygen forms diatomic molecules. But I am confused about $\ce{Na}$? So I would like to know about that.
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1answer
367 views

Element with No Proton?

On seeing this graph closely I noticed the there a element with no proton. But with no proton there will be no electron too and don't think that an lone neutron would form an element. So is that ...
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1answer
48 views

units of mass on the atomic scale

what are the systems of recording atomic masses and their units? I know that the nucleon number is the number of protons and neutrons I also know that the mass number on the periodic table is the ...
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1answer
144 views

electron passing nodes?

When one say that the electron goes from 1 orbit , say 2S, to another (higher) orbital, say 5P, it mean that the electron is excited to that orbit by some mean. In doing so it also it will also cross ...
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1answer
56 views

Electron vs electron density

I recently read somewhere that electrons do not exist. it's just the electron density. Is it true that there are no electrons (particles) but only in the form of electron density? And does this ...
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1answer
55 views

What is continuum in line spectra?

I read that continuum in line spectra is noticed beyond a certain limit. What does it mean?
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Is there an algorithm for ascertaining the relative size of an atomic/ionic radius?

To the best of my knowledge, the following properties affect atomic radius. The grounded-state size of the valence electron shell. The Coulomb force of the core electrons less the Coulomb force of ...
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1answer
115 views

Why do ion cores not move in a metal?

The delocalized electrons in a metal move about because of the electrostatic attractions between them and many different positive ion cores. But why does the same not occur with the ion cores ...
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Molecules from atoms [closed]

Why do 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 $\ce{NaCl}$ while two chlorine atoms are required to combine with one ...
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1answer
73 views

Calculating edge length of a cube atom

This question comes straight from a worksheet we were assigned in chemistry, though it’s more math focused of a question I hope that this is an appropriate question to ask here. Calculate the edge ...
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1answer
84 views

Why is Astatine monoatomic?

I learnt that halogens always form covalent bonds to becoms diatomic molecules. So why is astatine monoatomic? I mean they have the same properties, why shouldn't they all be diatomic?
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560 views

Really how rare are hydrogen atoms?

Hasok Chang, a chemist, but perhaps more a philosopher recently published the book Is Water H2O? . Chang used the question and an extensive web of arguments ultimately as a platform to support a ...
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97 views

How many hydrogen atoms are in a sample of NH3?

How many hydrogen atoms are contained in 8.66 moles of $\ce{NH3}$? The answer is given after the log has been taken, so the final answer is 25.19. What I have been doing is multiplying 8.66 by 6.02 ...
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1answer
46 views

Placing the atomic mass and number of an element… [closed]

Why are the atomic and the mass numbers of an element flipped in the textbooks relative to the periodic table?
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1answer
147 views

What is there in an atom between the nucleus and electrons?

As you can see the atom consists not only of the nucleus and electron but also of "empty space is the space empty or is their something else?
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1answer
48 views

Atomic number $Z$

If electrons were spin-$\frac {3}{2}$ instead of spin-$\frac {1}{2}$ , what would be the atomic number $Z$ for the first noble gas ?
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Why does ionization energy increase as we go from left to right in a period?

Why does ionization energy increase as we go from left to right in a period? In my textbook, the explanation is as follows: "This is consistent with the idea that electrons added in the same ...
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2answers
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Interaction radius of a molecule

What is the most commonly used radius of an atom or molecule to describe the area that must touch another area of another molecule for the two to react. Is there one radius that always works or does ...
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1answer
164 views

Usefulness of the outdated Bohr model?

Whilst the Bohr model is incomplete and incorrect, it had limited usage in predicting spectral lines. In the same way, could it possibly with limited accuracy, be used to predict the outcome of ...
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1answer
52 views

How was it determined that the electron observed in the cathode ray experiments was the same particle that gave an atom its balancing negative charge?

How was it determined that the electron observed in the cathode ray experiments was the same particle that gave an atom its balancing negative charge? Couldn't there have been an entirely different ...
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172 views

Diatomic Molecules/Elements

What is the difference between diatomic molecules and elements? Also, If oxygen is element of a single atom, then what makes it a diatomic element? But, then I read that a single oxygen atom can ...
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1answer
414 views

Why are so many wave functions associated with hydrogen?

According to Wikipedia, there's an infinite set of possible wavefunctions (orbitals) for the hydrogen atom: $$\psi_{n\ell m}(r,\theta,\phi) = \sqrt {{\left ( \frac{2}{n a_0} \right ...
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1answer
54 views

How do atoms combine? [closed]

Do atoms combine with the nearest atoms possible because of lower delta E (less energy needed to form a stable nucleus)?
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1answer
97 views

Are the energies of orbitals that are not filled in an atom, equal?

In a hydrogen atom only 1s orbital is filled. Does this mean that the energies of all other orbitals are equal? If so,why?
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1answer
74 views

Isn't the mass of a carbon 12 equal to a mass of 6 neutron + 6 proton + 6 electron?

The mass of Carbon 12 is 12u from definition, and is formed with 6 neutron, each with 1.0087u, 6 proton, each with 1.0072u and 6 electron, each with 0.0005u, which all add up to 12.0894u. why is there ...
5
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1answer
72 views

How were the absolute masses of atoms calculated before the mass spectrometers?

I understand that true (non-relative) masses of atoms are calculated with a mass spectrometer. using this relationship: Centripetal Force = Force due to magnetic field(B) But I was wondering how ...
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23 views

Correlation between crystal structure and underlying atomic properties

Can the crystal structure of an element/metal be explained by any underlying atomic or quantum mechanical properties of the element or is it an intrinsic property by itself (like atomic number)?
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1answer
152 views

Can we make Gold in a Lab? [duplicate]

Can we make Gold in a Lab? Is it possible to make changes in metals that will create Gold? and How? I have tried to search something related to this but didn't get any good results. Thanks in Advance
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Does Uranium ore count as a mixture?

I'm doing an assignment where we must research the separation of a mixture to obtain a useful final product. I thought about the separation of Uranium from its ore after it has been mined, but I did ...
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1answer
142 views

Do multielectron atoms have nodes?

For hydrogen, other than in the 1s state, the electron wavefunctions have radial and/or angular nodes where the electron probability density is zero. In helium or further atoms with more than one ...
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Density Functional Theory with Generalized Gradient Approxmations (GGA) - What Happens if the Electron Density Shows a “Kink” at the Ion Position?

My question may be stupid, so please correct me if you find anything which is obviously erroneous. In the following I will place a question mark (?) besides points/steps I consider doubtful. My ...