Questions tagged [atomic-structure]
For questions about the various atomic structure theories, including the Bohr theory. Not to be confused with the actual arrangement of atoms in macroscopic solids ([solid-state-chemistry]) or newer quantum concepts ([quantum-chemistry])
244 questions
-1
votes
1
answer
60
views
Excitation of electron when the next higher shell is full
Take $\ce{[Ne] 1s^2 2s^2 2p^6}$. If I input the $1$st excitation energy to the $1$st shell electron where will it go? And what would happen since the $2$nd shell is already filled?
For example I give $...
- 11
1
vote
0
answers
62
views
Is it correct to say that the gold foil experiment identified the nucleus’s volume relative to the atom?
In my studies, I came across the statement: “The volume of the nucleus relative to the atom can be identified using the gold foil experiment.” I’ve been considering whether this is accurate or ...
2
votes
0
answers
60
views
What exactly is going on during electron coupling?
Straight to the point: It's hard for me to imagine physically what electrons are doing when they "couple". Is an unpaired electron from one orbital essentially moving to an orbital with ...
0
votes
1
answer
85
views
Why is the duplet or the octet rule real? It feels totally counterintuitive?
I am 9th grader from India,
My chemistry text [by Dr.V.J. Dalal] states about something called as the octet rule:
It tells that
an atom needs to have eight electrons in its outermost shell [except $H$...
0
votes
0
answers
43
views
How exactly mutually shared electrons revolves around nucleuses? [duplicate]
In the first year, this question stroked my brain again. I have asked this question to my chemistry teacher on how exactly shared electrons move when it forms a covalent bond. He said, it is maybe ...
9
votes
3
answers
2k
views
Why don't we observe protons deflecting in J.J. Thomson's experiment?
I have been told that in J.J. Thomson's experiment of the discovery of the electron, he took 2 metal plates, an anode and a cathode, put them in a CRT, and then supplied a high voltage with opposite ...
- 101
1
vote
0
answers
17
views
Will an electron release energy when it is added into an atom for which electron affinity value is negative (endothermic)?
According to my understanding, when an electron is added into an atom, it emits energy in the form of photons because it is a form of de-excitation or relaxation. This is when electron affinity will ...
- 469
10
votes
1
answer
949
views
Sargent-Welch 1947 atomic model kit, design and use
I collect and use vintage atomic / molecular model kits eg by Catalin, Courtaulds, Sargent Welch etc. These all represent molecules but intrigued by this Sargent Welch set (link below) dated 1947 ...
- 111
-2
votes
1
answer
102
views
Why do we only use the principal quantum number to calculate the energy of an electron in an H atom? [duplicate]
According to my high school textbook the energy of an electron in a hydrogen atom is $E = -13.6/n^2~\pu{eV}$, where $n$ is the principal quantum number of the orbital in which the electron is present.
...
1
vote
1
answer
65
views
Sign Conventions for Electron Affinity and Electron Gain Enthalpy [duplicate]
In some of the books, negative sign is used for an exothermic Electron Affinity. But in others, a positive sign indicates an exothermic Electron Affinity. Now if we adopt the first sign convention of ...
- 469
-1
votes
1
answer
144
views
How does an electron's distance from the nucleus depend on angular quantum number?
My school teacher told us this and I couldn't get his reason:
The average distance of an electron (belonging to the same orbit) from the nucleus decreases with the increase in the value of angular ...
- 127
-3
votes
1
answer
71
views
Question from J. D. Lee about Quantum Numbers
There's this question in J. D. Lee: Concise Inorganic Chemistry, which I haven't understood exactly.
Which of the following may have the same set of quantum numbers?
The last electron of scandium and ...
0
votes
1
answer
102
views
Perforated Cathode in Anode Ray Experiment
While studying about the anode ray experiment (E. Goldstein), I had a doubt pop up in my head. In the experiment, a perforated cathode has been used. What is the exact reason behind that? Upon ...
- 99
0
votes
2
answers
145
views
What does "predicted" mean in an electronic configuration?
I've noticed the term "(predicted)" appearing at the end of electron configurations for heavier elements. Could you explain what it signifies and the reason behind it? I haven't been able to ...
- 140
4
votes
2
answers
245
views
Replacement of a nucleus with electrons by an effective nucleus
This question was asked in my test:
In a lithium atom the outer electron is in the second orbit. The interaction of this outer electron with two inner electrons can be accounted for by assuming that ...
- 173
0
votes
2
answers
127
views
Find element atomic mass from compound
I bought a 1962 Nuclear Power Engineering by EL-Wakil
There is an exercise that reads:
Four compounds of one element contain 90.3, 16.5, 26.4, 22.87 per cent of that element by mass. The corresponding ...
- 19
1
vote
1
answer
187
views
Wave function in Schrodinger's model
I am trying to wrap my head around the Schrodinger's quantum mechanical model of an atom.
According to the NCERT$^1$, the Schrodinger's equation is given by:
$$\hat{H}\Psi=E\Psi$$ where $\hat{H}$ is ...
- 830
1
vote
1
answer
76
views
The existence of a principal quantum level or energy shell after the loss of an electron from the outer shell of an atom
With the loss of an electron from $\ce{Li}$ ($\mathrm{1s^2\ 2s^1}$), we get $\ce{Li+}$ ($\mathrm{1s^2}$), then the 2nd shell where the electron had been revolving in $\ce{Li}$ will get disappeared or ...
0
votes
1
answer
109
views
Can certain spectral lines be common between two spectrums
I have studied regarding atomic spectroscopy in my class and the Rydberg's formula. Suppose if I take $\ce{H}$ and $\ce{He+}$ and an electron jumps from from 2nd to 1st shell in $\ce{H}$ and from 4th ...
1
vote
1
answer
115
views
Electronic configuration and symmetry labels of $\mathrm{3d^7}$ ions
In $\mathrm{3d^7}$ ions, e.g. $\ce{Co^2+}$, the ground state is $\mathrm{^4F},$ and it contains different levels such as $\mathrm{^4T_{1g}},$ $\mathrm{^4T_{2g}}$ and $\mathrm{^4A_{2g}}$ due to the ...
- 11
-3
votes
1
answer
94
views
How does the concept of the electron shell (also called energy level) and the orbital coexist? [closed]
Running into a bit of confusion trying to understand the atomic structure and the root cause is mostly related to orbitals and energy levels.
At a basic level, I was taught that electrons orbit the ...
- 5
-3
votes
1
answer
42
views
Choosing energy levels for finding quantum numbers
When an element has multiple energy levels (i.e Titanium has $(Ar)3d^24s^2$), what energy level do we use to find the quantum numbers? Is it generally assumed the LAST energy level is used? or is it ...
3
votes
1
answer
430
views
If charge is quantised, how can It delocalize?
As I was trying to understand resonance, I got to know that it was imaginary phenomenon and it is just a tool to explain mechanisms and structures that are unexplained by Lewis dot structures or ...
- 177
-1
votes
1
answer
195
views
Convergence limit of emission spectra for atoms with multiple electrons
In high school chemistry, students are taught that the convergence limit in the emission spectrum of an element can be used to determine the first ionization energy.
However, what about the second, ...
- 248
4
votes
1
answer
276
views
Eigenfunctions of total angular momenta as linear combinations of Slater-determinants
In the Hartree scheme for many-electron atoms, the approximated Hamiltonian (in a.u.)
$$\hat{H} = \sum_{i=1}^Z \left(-\frac{1}{2} \nabla_i^2 -\frac{Z}{r_i} + V_\text{H}\left(r_i\right)\right)$$
is ...
- 41
-2
votes
1
answer
367
views
Graph of kinetic energy of ejected electron vs intensity
While studying photoelectric effect I got a doubt in the graph of kinetic energy of ejected electron vs the intensity of electromagnetic radiation.
Everywhere this graph is given as
But here for 0 ...
- 39
5
votes
1
answer
98
views
Atomic terms and perturbation theory
I have a question about the derivation of the possible atomic terms of an atom. Consider an atom with $N$ electrons in the central-field approximation, with hamiltonian
$$
H_{0} = \sum_{i=1}^{N} \left[...
- 461
2
votes
1
answer
101
views
Stark and Zeeman effects and their causes
In high school we are taught that Zeeman and Stark effect directly lead to the findings of further divisions of an electron's shell in an atom.
What is exactly the reason that causes the spectral ...
- 93
1
vote
1
answer
492
views
Why hot iron turns from red to white and then blue? [closed]
While reading structure of atom chapter no. 2 from ncert class 11th chemistry part 1 book, I got a doubt. In the book it says on page 40 that:
Hot objects emit electromagnetic radiations over a wide ...
- 39
2
votes
3
answers
624
views
Distance of Orbitals from Nucleus relation with Energy level and penetration power
I have studied that according to Aufbau rule the energy of subshells is dependent on the sum of $ n $ and $l$ values. This would imply that the energy of subshells in a shell varies as
$$ ns \lt np \...
- 35
-2
votes
1
answer
91
views
Can't the wavelength of an electron increase or decrease to "fit" the wave perfectly in any radius?
I was reading about how de Broglie's electron-wave theory explained the quantisation of energy in a Bohr atom. What I understand is as follows:
If the wave is to be arranged in the form of a circle ...
- 101
0
votes
1
answer
133
views
Are there compounds distance functions to define a compounds space metrics
Is there exist something like a distance function for compounds, computing a number for any two given molecules? Such a function would measure dissimilarity at the atomic structure and bonds levels, ...
- 195
0
votes
0
answers
68
views
Can someone elaborate what it means when its said that electron shells do not exist in multi electron systems?
I'm an undergraduate student in chemistry. I'm trying to grapple with all the new stuff we're learning and making sense of it. Now I want to know if electron shells really "exist" in multi ...
- 29
1
vote
1
answer
153
views
Why are orbits shown out of plane in popular cartoons of atomic structure? [closed]
The (former) U.S. Atomic Energy Commission had a seal showing a symbolic view of the atom that is unrealistic but instantly recognizable:
Source: https://blog.nuclearsecrecy.com/2012/04/13/friday-...
- 42.3k
0
votes
1
answer
702
views
How does O2- have the largest radius [closed]
Why is the correct option O^2-, aren't all of them equal since they all have the same number of energy shells and same number of electrons in them
- 19
3
votes
1
answer
322
views
Is there a difference between Hartree-Fock method and LCAO?
I have to dive in some quantum chemistry for a quantum machine learning project and I came across the so-called Hartree-Fock method.
In one of the reference I used, they considered electrons as ...
- 49
-2
votes
2
answers
542
views
What is the difference between alloying and doping? [closed]
When compared to doping, how is alloying different? What modifications to the structure are brought about by both of these?
-2
votes
1
answer
144
views
How can Planck’s equation and the wave equation simultaneously coexist with contradicting each other? [closed]
The equations:
E=hf (Planck’s equation, where E is the energy, h is the Planck’s constant and f is the frequency) and
V=fλ (where v is the speed (in a vacuum), f is frequency and λ is the wavelength) ...
1
vote
1
answer
78
views
How does bond formation affect the energetics of the bond?
I am an 11th grade student who has just started learning about bonds in compounds. My question pertains to a line written in JD Lee's Concise Inorganic Chemistry for JEE (Main and Advanced)
It was ...
- 29
-2
votes
2
answers
973
views
Why silicon doesn't have the electronic configuration [Ne] 3s¹ 3p³?
I have read that half or fully filled orbitals provide more stability to the element due to symmetry and exchange energy.It is the reason for electronic configuration of Cr-[Ar]4s¹3d⁵.
Then, why doesn'...
- 1
-4
votes
1
answer
988
views
What Are Angular Nodes , Radial Nodes, Nodal Plane and Nodal Surfaces? [duplicate]
Actually, i am confused between all of them. some says that angular node is same as nodal planes and radial nodes is same as nodal surfaces... and what's the difference between nodal planes and nodal ...
-2
votes
1
answer
78
views
Electrons in Bohr's atomic model [duplicate]
Why electrons don't fall into the nucleus in bohr's atomic model?
Is there a reason or explanation or is just a consideration?
user126889
1
vote
1
answer
304
views
Why the electronic configuration of samarium is ending with 4f⁶6s²
What is coming in my mind is that 4f^7 6s^1 should be more stable as it allows two orbitals to be half filled rather than 4f^6 6s^2 in which only one orbital is completely filled....can someone please ...
- 73
1
vote
0
answers
123
views
Why is it impossible to determine number of visible emission spectrum of He+
We know that atoms emit spectral lines on excitation and de excitation.
I was doing one high school question based on this theory
Number of visible lines when an electron returns from 5th orbit upto ...
- 69
3
votes
2
answers
302
views
Why is radial probability density exactly zero at the center?
I have read that the radial probability density is exactly zero at $r = 0$ because the radial probability density is
$$P(r) = \psi^2\,\mathrm dv,\tag{1}$$
where $\mathrm dv$ is the volume of spherical ...
- 53
1
vote
0
answers
30
views
Which ionic radius is most relevant for anticipating co-crystalization?
In the context of anticipating the likeliness that elemental impurities co-crystalize into the crystals containing an element of similar radius (see this question), which is the relevant radii to ...
- 1,107
0
votes
2
answers
549
views
Proof for equation of radial probability distribution curve
So my textbook says the equation for this is
$$P(r) = 4\pi r^2\Psi^2 $$
It also gives the volume of the shell formula
$$\mathrm{d}V = \frac 43 \pi(r+\mathrm{d}r)^3 - \frac 43 \pi r^3$$
which I ...
- 11
-3
votes
1
answer
718
views
Which quantum numbers does the orbital angular momentum depend on? [closed]
I learned from a question that I recently solved that the orbital angular momentum depends on both the azimuthal and magnetic quantum numbers.
I did not expect this because the formula for the orbital ...
user125086
4
votes
1
answer
446
views
Excitation of hydrogen atom
I studied the Bohr's model of atom that says electron can jump to higher energy level by absorbing photon, but the quantum model says we have more than that (quantum numbers). Therefore, when the ...
- 61
4
votes
1
answer
471
views
Huge variation of the atomic size of Uranium
I've already posted this question in Physics Stack Exchange, but the answer that I received (actinide contraction similar to lanthanide contraction) is not convincing for me, or at least is not ...
- 606