Questions tagged [atoms]

Smallest particle still characterizing a chemical element. It consists of a small nucleus charged positively, carrying almost all of the atom's mass, with electrons surrounding it. This tag should be applied to questions that specifically concern atoms or their properties. For the charged particles, please use [ions] instead. If your question is specifically about [protons], [neutrons], or [electrons], use those tags instead.

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2answers
125 views

What is physically responsible for different compounds with the same types of atoms?

I only have a GCSE in Chemistry but I have discovered a lot of resources myself. One thing I cannot find an answer to is this: What is physically responsible for the different compounds you can get ...
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1answer
407 views

Bohr Radius Confusion

I saw online that the radius for each level is defined by the formula: $$r_n=n^2 r_1$$ Where $r_1$ is approximately $53\ \mathrm{pm}$. However, on the Barron's AP chemistry book 7th edition, it ...
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2answers
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is there any boundary or membrane around atom to recognize its shape?

we know that every Isolated atoms are spherically symmetric.how we know its shape, is there is any membrane covers it as skin of our body?
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Rutherford's Alpha Ray Scattering Experiment

I understood the result of this experiment that the nucleus is nearly empty and things like that. But what I have on mind is that when an alpha particle goes nearer to the thin gold foil why couldn'...
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1answer
510 views

Does the shielding effect affect atomic bonding?

Electrons within an atom don't experience the full charge of the nucleus due to the shielding effect? Likewise, when creating atomic bonds, does the shielding effect affect the attraction between two ...
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1answer
253 views

Spin quantum number of electron

Why is the spin quantum number of an electron +1\2 or -1\2 in an atom? Is this an experimental value or theoretical value?
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0answers
953 views

Why does q/m ratio(specific charge) depend on nature of gas in anode ray experiment?

I can't understand why $q/m$ ratio changes in anode ray experiment (discharge tube experiment) (which was carried out by Goldstein) with change in nature of gas? Since $q=1.6\times10^{-19}\ \mathrm C$...
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1answer
7k views

When was the amu renamed the dalton? [closed]

I taught chemistry for 30 years and never encountered the unit until I saw it on a juice bottle!
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2answers
1k views

NMR chemical shift range of different elements

A typical $\ce{^1H}$ NMR runs from approximately 0 to 10 ppm, give or take a bit. $\ce{^13C}$ NMR runs from 0 to 200. And $\ce{^59Co}$ NMR runs from -5000 to 15000 ppm! There seems to be some ...
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1answer
940 views

Charge to mass ratio of an electron

The charge to mass ratio of an electron is -1.7588×10^8 coulomb/g, and is fixed. My textbook, however says that as the speed of an electron increases, the value of charge to mass ratio increases. How ...
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1answer
676 views

Reasons for weakness of London dispersion force in graphite?

The layers of graphite are held together via London dispersion force. This force is weak. I know carbon having a smaller atomic radius and few electrons is one factor for this force's weakness. But, ...
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502 views

How does symmetry of half filled and fully filled orbitals lead to stability

I googled a lot about why symmetry of half filled and fully filled orbitals decreases their energy but every time it is repeated that symmetry leads to stability. So the question is why symmetry leads ...
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1answer
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Do electrons in an atom revolve around the the nucleus clockwise or counterclockwise? [closed]

Do electrons in an atom revolve around the the nucleus clockwise or counterclockwise? Is there any rule to determine?
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The mass of carbon atom [duplicate]

I was reading Silberberg's principles of general chemistry when I noticed that it says that the mass of carbon12 is exactly 12 amu. But when I calculated the total mass of its components (6 protons ...
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1answer
983 views

Effects of Changing Avogadro's Constant

The Avogadro project suggests that we redefine the Avogadro constant to be equal to our best known estimate, $N_\mathrm{A} = 6.02214179 \times 10^{23}$, and redefine the kilogram based on the Avogadro ...
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1answer
15k views

Why is molar mass the same as atomic mass? [duplicate]

I am completely confused about why molar mass is the same as atomic mass. Could someone help explain why, thoroughly, but in simplified terms?
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1answer
221 views

Fundamentals of Li-ion Functionality

I would like to have an in-depth understanding of Li-ion batteries functionality, at atomic level. Can anyone help me to understand it? I have included some known background to support my questions. ...
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0answers
179 views

How to derive the electron density of Hooke's atom?

Hooke's atom has the following wave function: $$\Psi( \boldsymbol{r_1}, \boldsymbol{r_2}) \propto \left( 1 + \frac{|\boldsymbol{r_1} - \boldsymbol{r_2}|}{2} \right) \exp\left(-\frac{(r_1^2+r_2^2)}{4}\...
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1answer
2k views

Brackets in chemical formulas

When you have brackets such as $\ce{Zn(NO3)2}$, if there is a coefficient around the formula such as $\ce{2Zn(NO3)2}$, how would you read this? Would there be 2 zinc atoms, 4 nitrogen and 12 oxygen ...
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1answer
4k views

The mass of a carbon-12 atom is 12 amu. What percent of the mass is located in the nucleus?

The mass of a carbon-12 atom is 12 amu. What percent of the mass is located in the nucleus? and Why is the value so close to 100%?
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3answers
54k views

How to calculate the number of atoms of each element in a urea?

I have a stoichiometry question which I answered incorrectly and I am not sure where I went wrong. The question is as follows: Urea, $\ce{(NH2)2CO}$, is used for fertilizer and many other things. ...
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1answer
884 views

What are the physical manifestations of radial nodes?

I realize that nodes (both angular and radial) are areas with zero probablility of finding an electron. I realize that plotting the square of the radial eigenfunction for an orbital will give the ...
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2answers
290 views

Atomic Orbitals

I read in a textbook that after an electron jumps to a higher energy level when supplied with high temperatures or current, they again fall back to their respective energy level by losing energy and ...
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0answers
3k views

Inter electronic repulsion in s and d orbitals

This was written in a lecture slide: Two electrons present in the same d-orbital repel each other more strongly than do two electrons in the same s-orbital. Why is there a difference in the amount ...
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1answer
675 views

NMR Splitting for Adjacent, Equivalent Hydrogens?

Why don't chemically equivalent hydrogens on adjacent carbons split the 1H NMR signal? There appears to be an answer here, but I'm having trouble understanding it because I cannot rationalize what ...
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1answer
154 views

Consequences of a neutron decay (beta radiation) and reasoning for an electron capture

I came about the following doubts (extremely comprehensive in nature) in a logical sequence, so I have made it a point to explain either in full detail and then proceed to the interrelation between ...
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2answers
23k views

Is there a difference between energy levels and electron shells?

Is there any difference between energy levels and electron shells, or do they mean the same thing? Does the number of energy levels remain constant when progressing across a period?
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1answer
10k views

Why does cobalt have a higher atomic mass than nickel?

I understand that this deviation from the general trend of increasing atomic number and atomic mass is because cobalt's isotopes tend to have more neutrons than nickel's. Why is that the case? How ...
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2answers
918 views

How to convert metre to ångström? [closed]

In my book it says Convert $1.213\cdot10^{-11}$ metre into Angstrom. The answer is $12.13\cdot10^{-2}$ Angstrom. How is it possible? I thought of multiplying the metre with $10^{-10}$, but I ...
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3answers
329 views

Computational methods to obtain relative energies of electronic configurations of atoms

When one learns the Aufbau principle to “predict” electronic configurations, and the $(n + \ell)$ ordering rule (or Madelung rule), one also learns of the exceptions to the rules… some of which (Cr, ...
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2answers
138 views

In Chemistry, is it possible to use the old representation of the atom as a nucleus surrounded by orbiting particles?

In Physics, Newton's laws are enough for many applications. Sometimes, relativity must be used instead or complementary, and sometimes, Quantum Mechanics. Is this the same case with Chemistry? Are ...
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1answer
2k views

Range of distance for Van der Waals force

Is there any range of distance between the nuclei of the atoms (in Angstrom, say between 4 to 12 Angstrom) within which there will be an occurrence of Van der Waals force (attraction) between them? ...
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2answers
1k views

Why don't the electrons of opposite spins collide in an orbital?

As I was reading through my textbook, I got to know that in an orbital, there are 2 electrons of opposite spins. My question is: Shouldn't they collide whilst they are rotating?
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1answer
311 views

Determination of initial excited state via luminescence

A one electron species initially in the some excited state ($n_i$) is irradiated with a light of wavelength 121 nm when the electron is promoted to a further higher orbit ($n_f$). In ...
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2answers
8k views

Transition from ground state to excited state

I don't understand how to correctly find the term symbol of an excited state. I know that the first two permitted transitions for the Ne atom are 16.8eV and 19.8eV and I want to find the electronic ...
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3answers
1k views

Stability of Bohr Orbits

In class we had been taught that Rutherford's model was unsuccessful because it failed to show that the orbits are stable because the electrons would lose energy because of electromagnetic radiation. ...
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2answers
1k views

Do hybrid orbitals exist in unbonded molecules? What would they look like?

For example, the ground state of a neutral carbon atom could be notated as: $$ [\ce{He}] \underset{\ce{2s}}{[\uparrow \downarrow]} \underset{\ce{2p}}{[\uparrow \vert \uparrow \vert \; \;]} $$ I ...
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2answers
1k views

How do EM waves cause molecules to rotate, move, and cause electrons to move up energy levels?

Atoms can absorb electromagnetic waves to cause electrons to jump up energy levels, when electrons go down energy levels they release a photon. But how do EM waves cause atoms to rotate, and vibrate?
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6answers
24k views

Why do atoms need 8 electrons to stabilize? [duplicate]

As the title says. I have surfed all of the net but could never find the answer to this question. Why do atoms need 8 electrons to stabilize? I mean why not 7 or 5 or 10 electrons? Why specifically 8? ...
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1answer
1k views

Why does greater orbital overlap mean a stronger bond?

According to valence bond theory, orbital overlap produces a bond. However, I don’t understand why having greater orbital overlap renders a bond stronger. It’s intuitive, I suppose, but I haven’t been ...
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1answer
256 views

Base Peak Intensity different than higher value in Mass Intensity Map

I've been working with mass spectrum data analysis (but my field is computer science). I'm using a library that allows me to get the entire Mass Intensity of the MS1 scan (such as [time, intensity])....
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0answers
62 views

Does 12 amu really equal the mass of one carbon-12 atom? [duplicate]

As I was studying chemistry, I encountered atomic mass units (amu) and based on some calculations, I realized that some numbers don't work out. Apparently, 12 amu is the mass of a single carbon-12 ...
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3answers
2k views

Can the regions of 1s and 2s subshells overlap?

I was studying atomic orbitals and always had this question lingering. As we can see in the image, the 1s and 2s subshells both are known to closely surround nucleus. The overlapping peaks in the ...
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1answer
208 views

Avagadro's number [duplicate]

Ive been reading about moles and I can't seem to understand avagadro's number. I get that the idea is 1g of hydrogen, 12g of carbon, and 16g of oxygen would all have the same number of atoms, but why? ...
3
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1answer
258 views

Different masses for the same element and isotope?

I am watching this Khan Academy video on mass defect and binding energy, it uses helium-4 as an example to go through the concept. The person finds the predicted mass (protons + neutrons) to be 4....
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0answers
363 views

Understanding three-dimensional structure of common salt

I started reading through The Feynman Lectures and came across this diagram. What do the numbers next to the nodes in the diagram represent? It's not explained in the text. All that is mentioned is: "...
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1answer
2k views

Why did the alpha-particles in Rutherford's experiment not collide with the electrons? [duplicate]

In Rutherford's experiment to show the existence of nucleus in an atom, the alpha-particles were exposed on the surface of certain metal i.e. gold. He observed that more than 99% of these particles ...
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1answer
469 views

Spin of electrons about it's own axis, release of energy & COLLAPSE of atom? [closed]

An electron spins about it's own axis. So it has rotational accln. Thus, according to Maxwell's Electromagnetic Theory , Rotational Kinetic energy must be released. Thus, at some pt. of time , ...
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1answer
592 views

What is the reason why protons and electrons do not collide?

can someone give me an intuitive picture of why electrons don't collide with protons? I know that electrons move in a sort of cloud, which is our 'orbital', and that they mainly behave like ...
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0answers
245 views

Why are Alkali Metal Ions Soluble?

I think the question needs no elaboration. Why are salts containing Group 1A cations extremely soluble in water? I speculate that the reason involves the low charge density of those ions in a given ...

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