Questions tagged [orbitals]

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53 views

Why do I get the wrong expression for velocity of an electron in Bohr's $n$th orbit? [closed]

Why do I get the wrong expression for velocity of an electron in bohrs nth orbit? Putting $r = \frac{nh}{mv\cdot2\pi}$, we get \begin{align} \require{cancel} \require{siunitx} mv^2 &= \...
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1answer
202 views

How to calculate expected angular momentum for $d_{x^2 - y^2}$ orbital

I know that the expectation values of $L_x, L_y, L_z$ are $0$ for a $d_{x^2 - y^2}$ orbital, but how is this done using algebra? In other words, can someone show me how $<d_{x^2 - y^2}|\hat{L_z}| ...
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464 views

If electrons are unstable in a higher energy state, why do they attain those excited states?

Electrons can absorb energy (discrete) to jump from lower energy states to higher. Once they reach higher energy states they become unstable and jump to their ground state by emitting photon (of ...
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1answer
1k views

Expectation value of $1/r^3$ in the $2p$ state of a Coulomb potential

I've been having difficulty calculating this quantity. We have an electron in the 2p state of a hydrogen atom (Coulomb potential). As a preliminary step to finding the energy difference between the $...
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1answer
133 views

Why is the Dresselhaus type spin orbit coupling represented as next-nearest neighbor hopping?

As I have seen it in the Fu-Kane-Mele model context of a bipartite lattice, it is represented as a coupling between second-nearest neighbors $\langle\langle i,j\rangle\rangle$, like so: $i \lambda \...
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1answer
1k views

Can radius of electron orbit in hydrogen atom shrink below the bohr's radius?

When we apply magnetic field to a hydrogen atom such that the Magnetic Lorentz Force acts inwards on the electron, will its radius shrink to a value lesser than the Bohr's radius, because according to ...
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1answer
93 views

Orbitals and electron jumping

Bohr model (tries to) explain how electron goes to higher state(orbit) from lower state(orbit) on photon absorption.But in quantum mechanics, we have orbitals which can at most accommodate 2electrons. ...
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0answers
89 views

How are hybrid orbitals more energetically favorable than their components?

In the orbital hybridization theory, the $s$ and the $p$ orbitals are said to combine to form hybrid orbitals which are degenerate in energy. How does the linear combination of the $s$ and $p$ ...
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3answers
77 views

About the energy of electron [closed]

According to Einstein the total energy $E=mc^2$. Now my question is why don't their exist any orbits with fractional values such that they satisfy the above Einstein's equation, even though the ...
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1answer
194 views

Why spin-orbit coupling in TMDCs is strong?

I already know about spin-orbit coupling in QM. Spin-orbit coulping is that spin of electron and it`s orbital(angular momentum) are considered for getting Hamiltonian which can cause energy splitting. ...
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1answer
176 views

Do different orbitals overlap in multielectron atom? [duplicate]

We know that there are many kind of orbitals and we also know that these are regions of maximum probability where an electron can be. Orbitals are plotted generally on XYZ plane. The doubt arises ...
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1answer
132 views

The phases from ladder operators and the spin orbit coupling for p orbitals

In this question, I am concerned with $p$ orbitals ($l = 1$) and so I shall use the notation $|0\rangle$ to refer to the state $l = 1, m = 0$ and so forth. When defining the ladder operators, the ...
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2answers
483 views

How does covalent bonding actually work?

How does covalent bonding actually work? Consider the molecule $O_2$, which has a double covalent bond between the oxygen molecules. Chemistry texts say that a double covalent bond occurs because this ...
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1answer
32 views

How does geometry affects the energy content of an Orbital?

My chemistry books state without giving any reason that due to its' Bell shaped(2d:planar*) structure p_orbital possess more energy than s -orbital?(speherical/ 2d:circle) So how does geometry ...
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1answer
66 views

The Existence of the $^1D$ term and the non-existence of the $^3D$ term?

Yesterday I asked this question concerning the existence of terms. This question is on the same topic. I have been looking at some tables (in Yang and Hamilton (2010), pg 199) at the terms that exist ...
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1answer
46 views

Using $M_L$ and $M_S$ to determine existence of terms

When it comes to deciding which terms exist for a given configuration I have often seen an argument along the following lines: For the configuration $np^2$ with $S=1$ it is impossible to form a ...
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2answers
514 views

Is the electron in an atomic orbital moving or not?

I have debated quite a lot with friends on this question and the answer is still unclear. On hand the electron wave fonction is delocalized on the orbital (let's say the one in the H atom e.g.), so ...
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3answers
251 views

X-ray absorption only at single k-edge

I'm doing a Monte Carlo simulation of a transmission type x-ray tube. A electron beam hits a thin tungsten target, causing X-rays to be emitted. These X-rays then transmit through the target and a ...
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2answers
6k views

Is there actually a 0 probability of finding an electron in an orbital node?

I have recently read that an orbital node in an atom is a region where there is a 0 chance of finding an electron. However, I have also read that there is an above 0 chance of finding an electron ...
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3answers
648 views

Quantum jump of an electron

I read about the quantum jump of electrons and in my books it is written that when an electron is hit by a sufficient amount of energy or EM wave, it jumps to the next orbit and then it cannot stay in ...
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0answers
60 views

Why completing an octet stabilises an atom, quantum mechanically? [duplicate]

They say that Neon $Ne$ is stable because it has 10 electrons and with 10 electrons it completes its octet and completing an octet decreases the potential energy of an atom to the minimum and a system ...
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2answers
101 views

Can atomic orbitals of an isolated atom rotate relative to the nucleus?

I am a beginner at orbitals. It seemed interesting to me while studying p orbitals that the texts don't suggest that the orbitals are rigid relative to the nucleus. But I thought mathematically these ...
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1answer
934 views

Exceptions to the Aufbau principle?

Why are there exceptions to the Aufbau Principle? How do the abnormalities occur and why? If you could specify a few exceptions that would be swell.
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3answers
3k views

Magnetic quantum number for d orbitals

Online one can find many pictures of d-orbitals. I know that these states correspond to : n = 3, l = 2, m = -2, ...,2 but I don't know which one is which and I couldn't find a clear asignment ...
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2answers
372 views

How is Bohr's model related to electron cloud models via the correspondence principle?

I came across a discussion of atomic Rydberg states, which appear to be defined as having their outer electron in a highly excited state. In the same text, it mentioned that these excited electrons ...
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4answers
446 views

Where do symmetries in atomic orbitals come from?

It is well established that: 'In quantum mechanics, the behavior of an electron in an atom is described by an orbital, which is a probability distribution rather than an orbit. There are also many ...
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1answer
2k views

Expectation values of $x$, $y$, $z$ in hydrogen?

The expectation value of $r=\sqrt{x^2 + y^2 + z^2}$ for the electron in the ground state in hydrogen is $\frac{3a}{2}$ where a is the bohr radius. I can easily see from the integration that the ...
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0answers
56 views

Is it possible to reach orbit without turning the rocket?

A comment to this question sparked my interest. If we start a rocket from the surface at the equator, it has some angular momentum with regard to Earth. This angular momentum is definitely much too ...
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1answer
146 views

Quantum numbers and radial probability of the electrons

In this book it has been written: The $ns$, $(n − 1)d$, and $(n − 2)f$ orbitals are so close to one another in energy, and interpenetrate one another so extensively. And in the wikipedia article ...
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1answer
694 views

Removing electron from inner shell of an atom [closed]

Can we remove an electron from the inner shell of an atom without disturbing the outer orbital? If so, how?
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640 views

Electron Levels of Atomic Nitrogen Vs. Molecular Nitrogen

So I have a question about the the affect of the electron energy levels of Nitrogen when it becomes diatomic. In Figure 1 below you see the electron energy levels of atomic Nitrogen, and it shows that ...
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2answers
203 views

Iron has only 2 valence electrons… How did it became four?

http://youtu.be/bht9AJ1eNYc?t=24m50s at 24:50 said Iron has 4 electrons, Iron has only 2 valence electrons... How did it became four? Also... Why magnetic field of electrons don't cancel each other ...
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270 views

Kepler's laws at atomic level

If Coulomb's inverse square Law of forces operates between two electrostatic charges and at an atomic level as well (as in Newton's gravitational Law), has it been verified that Kepler's Laws which ...
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1answer
179 views

How do you observe an atom in an excited state?

Last week I posted this question which was massively downvoted. The downvotes appear to be largely motivated by an observation I made which was not essential to the question, but which seems to have ...
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1answer
1k views

How can an electron shell hold more than two electrons?

The Pauli Exclusion principle states in an atom or molecule, no two electrons can have the same four electronic quantum numbers. As an orbital can contain a maximum of only two electrons, the two ...
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1answer
2k views

Given that the atomic orbitals are fuzzy, why are the energy levels and energy transitions sharp?

Given that the atomic orbitals are fuzzy, why are the energy levels and energy transitions sharp?
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111 views

Why are orbitals are shown bubble shaped in the books when they exist in only in one particular dimension

I am utterly confused here: In our books orbitals $s$, $p$, $d$ are shown to be bubble or sphere like but ain't $s$-orbital exist only in $x$-axis so only a particular underline should be shown to ...
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1answer
96 views

What would the shape of a singly excited hydrogen atom be?

Suppose a hydrogen atom is excited up to a $\underset{1s}{[\;]} \underset{2s}{[\uparrow]}$ state which takes about 1000 kJ/mol. Due to electron shielding f orbitals tend to be higher energy than d ...
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2answers
418 views

How does an electron jump from one lobe to another of the same hourglass-shaped $2p_x$-orbital?

Imagine an electron in the hourglass-shaped $2p_x$-orbital. It has two lobes. The probability of it being in the centre of the orbital is zero. This is the point that connects the two lobes of the ...
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236 views

If orbital shells are just probability functions, why are quantum numbers only ever integers? [closed]

Quantum numbers are supposed to denote every individual orbital. But if orbital shells are probability functions, then orbitals can't be definite, solid things. So in that case, there can be variation ...
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1answer
312 views

Molecular Orbitals and Nodal Symmetry

I am currently doing a solid state physics class and am stuck on a concept regarding molecular orbital (MO) hybridization. As an example consider an HF molecule bonded along the z-axis. This molecule ...
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4answers
6k views

What is a standing wave?

I'm a highschool sophomore, bear this is mind when answering this question, in other words, the answer doesn't need to be in total layman terms, but it should be understandable by an applied ...
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1answer
153 views

Symmetries of atomic orbitals, s-state forms a triplet!

I have a trouble understanding how s-subshell electrons can form a triplet state ever. In general isn't it true, that there are only two cases for s-state: $\ell=0$, $s=1/2$, $J=1/2$ - doublet (one ...
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1answer
124 views

How much of the decay energy is left when the electron escapes to large distances?

During a neutron decay, there is distribution of KE of electron. When KE given to electron is $0.782~\mathrm{MeV}$ (max) , it escapes from proton field. A lot of this KE is used for Potential Energy. ...
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1answer
174 views

Is there a way to strip all the electrons from single atom with atomic number greater than 2

Please explain by what means electrons extraction can be done. How person can focus activity on single atom (from precision point of view) to do so? How at each step person can know how much electrons ...
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55 views

How can an orbital be recognised from the wavefunction notation?

I am a student and was working up the exercises in my book when I came across a problem that required me to identify the orbital given by $ \psi_{3,2,1}\,.$ What I can work out is that the sub-shell ...
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55 views

How does the filling of the 2p orbitals occur?

When electrons enter the 2p orbitals, electrons of the same spin occupy the 2p orbitals first and then electrons of the opposite spin fill up the orbitals. Why is that? My professor told me that there ...
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1answer
55 views

What factors relate the number of protons in the nucleons with the number of electrons in the orbitals?

Atoms always want to have a closed shell, because it requires low energy compared to the lattice enthalpy. How does this always match throughout the periodic table between the number of protons and ...
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Why does an electron shell further away from nucleus has higher energy level?

Using electrical potential energy $V=\frac{1}{4\pi \varepsilon_0} \frac{Q_1 Q_2}{r}$ , a particle further away from nucleus has lower magnitude of energy. Using Coulomb's law, a particle further away ...
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Why do electrons not fully fill up all the orbitals sequentially?

Why do electrons not fully fill up all the orbitals sequentially? By this I mean: why don't the electrons fully take up the previous orbit first and then move onto the next orbit? Take calcium for ...