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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])

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-2 votes
0 answers
46 views

What are low-lying orbitals?

I came across the term "low-lying orbital" in my readings in chemistry, but I'm unclear on its precise definition and significance. Could someone explain what qualifies an orbital as "...
1 vote
1 answer
84 views

Electronic configuration and symmetry labels of 3d$^7$ ions

In 3d$^7$ ions, e.g. Co$^{2+}$, the ground state is $^4$F, and it contains different levels due to the crystal field, such as $^4T_{1g}$, $^4T_{2g}$ and $^4A_{2g}$. Can anyone tell me what exactly ...
-2 votes
0 answers
24 views

Can electron tunneling be neglected in structural chemistry?

I found something puzzling when I was studying structural chemistry: In transition metals, the higher-energy electrons can more easily enter the atomic nucleus than low-level electrons. We calculated ...
-3 votes
0 answers
29 views

Understanding Quantum Numbers from Electron Probability Plots [closed]

For a hydrogenic quantum system, the probability of finding the election Dnl(r)dr in a spherical shell of radius r (with nucleus at its center) and thickness dr, is plotted against r (in units of in a ...
2 votes
1 answer
120 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 ...
1 vote
1 answer
216 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 ...
4 votes
1 answer
858 views

Angular momentum of an electron in an atom

The Orbital Angular momentum of an electron in an atom is given by $\hbar \sqrt{l(l+1)}$ and the Spin Angular Momentum is $\hbar \sqrt{s(s+1)}$. So what is the resultant Angular momentum of an ...
20 votes
0 answers
1k views

What is d-orbital collapse?

When I was perusing the works of Schwarz on atomic structure, I came across the unfamiliar term of d-orbital collapse. He describes it as a variation in energetic sequence from group 1 to 3 elements ...
0 votes
1 answer
102 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 ...
0 votes
0 answers
34 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 ...
-3 votes
1 answer
40 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
70 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 ...
4 votes
1 answer
270 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 ...
3 votes
1 answer
424 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 ...
-1 votes
1 answer
130 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, ...
-2 votes
1 answer
193 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 ...
5 votes
1 answer
87 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[...
4 votes
0 answers
2k views

Why Rutherford was shocked by results of gold foil experiment?

The way Rutherford's classic gold foil experiment has been presented (including by Rutherford himself) doesn't make sense to me. As many of you know, Rutherford famously described himself as being ...
2 votes
0 answers
71 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 ...
1 vote
1 answer
263 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 ...
2 votes
3 answers
411 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 \...
-2 votes
2 answers
665 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'...
-2 votes
1 answer
76 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 ...
0 votes
1 answer
131 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, ...
0 votes
0 answers
65 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 ...
1 vote
1 answer
147 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-...
0 votes
1 answer
472 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
-2 votes
1 answer
878 views

Comparison between Atomic Spectrum of Hydrogen and Alkali Metals

I posted a question on Chemistry Stack Exchange a while back. It was related to the naming of atomic orbitals. One of the answers to it mentioned a research experiment. The link to the question is ...
2 votes
1 answer
239 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 ...
-2 votes
2 answers
437 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?
1 vote
1 answer
186 views

hydrogen spectrum

In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series, Lyman series, Paschen series), What is common to the lines ...
2 votes
2 answers
617 views

Why are the relative masses of isotopes not close to whole numbers?

Understandably, the relative atomic masses of isotopes are often not close to whole numbers as they're adjusted for isotope abudandancy eg. $A_r(Cl)\approx35.45$. However, wouldn't one expect the ...
-2 votes
1 answer
120 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
70 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 ...
4 votes
1 answer
466 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 ...
4 votes
1 answer
616 views

Lother Mayer curve

While studying about atomic trends, I encountered the Lothar Meyer curve: If the covalent radius decreases across a period, why is the graph of atomic volume reaching local minima halfway in the ...
2 votes
1 answer
403 views

Explanation of the missing 1-s orbital electrons of carbon in the molecular orbital diagram of methane

Consider the molecular orbital diagram of methane, for example found here: I would like to know what happens with the two 1s orbital electrons of carbon in the molecular orbitals it is forming. Is it ...
-4 votes
1 answer
684 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
75 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?
1 vote
0 answers
111 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 ...
3 votes
2 answers
242 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 ...
1 vote
0 answers
25 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 ...
0 votes
0 answers
87 views

How are the energies of, e.g. the 4p orbitals of the first transition series, determined?

Take a first row transition metal, say manganese. The 4s and 3d orbitals are occupied in Mn; each orbital's energy can can be definitely determined by ionising that orbital, obtaining the resulting Mn+...
0 votes
2 answers
317 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 ...
-3 votes
1 answer
282 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 ...
3 votes
0 answers
267 views

Why does titanium have lower affinity than scandium?

Electron affinity of atoms in the same row usually increases with the atomic number until the shell or half-shell gets full, and then it drops down. Some transition metals are exceptions from the rule,...
5 votes
1 answer
254 views

Could a positron be made to stably orbit an atom? [closed]

Suppose you have a single atom of neon, argon or some other noble gas of your choice. While the entire atom is electrically neutral a nearby positron would probably be more strongly attracted to the ...
4 votes
1 answer
436 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 ...
0 votes
0 answers
79 views

A question regarding hydrogen emission and absorption spectrum

I have read in many articles as well as my textbook that when an electric discharge is passed through a sample of hydrogen gas it excites the electrons and glows emitting light.When this light is ...
0 votes
0 answers
137 views

Ratio of total energy to kinetic energy in hydrogen atom when the reference is changed

If in the hydrogen atom potential energy at $\infty$ is chosen to be $\pu{13.6 eV},$ then what is the ratio of total energy and kinetic energy (with the sign) for the first Bohr orbit? I think we don'...

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