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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How does s subshell not have a node in the center despite the nucleus being there?

In most images of 1s subshell I see that there's no node shown at the center, and even the formula n-l-1 gives 0 as the answer. But, isn't the nucleus ...
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5 votes
1 answer
384 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 ...
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4 votes
1 answer
425 views

Huge variation of the atomic size of Uranium

I've already posted this question in Physics Stack EXchange, but the answer that I receveid (actinide contraction similar to lanthanide contraction) is not convincing for me or at least is not ...
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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 ...
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1 vote
1 answer
101 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 ...
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-1 votes
1 answer
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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 ...
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1 vote
2 answers
89 views

Size of Orbitals, Making Intuitive Sense of Quantum Model, Nomenclature of Subshells in the Quantum Model

Alright, so I am doing the Quantum Mechanical (or what some people call the Wave Mechanical model) of an atom. There's this part where we have different zones of the probablity of finding electrons, ...
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9 votes
2 answers
555 views

How to find the orbital a given wavefunction represents?

We were given the following question in chemistry class (under the topic “Atomic Structure”): Which orbital does the following wavefunction represent? $$φ(r) = \frac{1}{81(6π)^{1/2}}\left(\frac{Z}{a}\...
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Ambiguity on determining a relativistic Dirac orbital's "shape" when it has two angular components

Wikipedia says that a relativistic Dirac atomic orbital is a 4-component vector, with two angular parts and two spin parts. It also says, indirectly, that 'the top two components of a 2p(1/2) orbital ...
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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+...
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2 votes
2 answers
89 views

Why are higher-energy orbitals larger in size/radius?

I know the different atomic orbitals of atoms are derived from the wave function in the Schroedinger equation. Because I'm not a mathematician, though, I can't decipher the Schroedinger equation and ...
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How do the odd proton-number elements originate?

I have a question about the origin of the odd proton-number elements in the periodic table, please. As it is generally thought that the big bang produces hydrogen first, and then hydrogen combined to ...
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How do we write spin multiplicity for Mn(2+), Mn(7+)?

Mn has atomic number = 25 Since it is an exception to electronic configuration , unlike having = $\mathrm{3d^7}$ , it has electronic configuration = $\mathrm{3d^5,4s^2}$. Formula for spin multiplicity ...
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What kind of electronic configurations are possible?

Let us take $d^6$ orbital as an example: A) ↑ | ↑ | ↑ ↓ | ↑ | ↑ | Now , this one 1 way. My Q is that how is it possible that in the 3rd box , we have a paired electron but not in the 1st one. Like it ...
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2 votes
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What will the correct value of spin quantum number for last electron of Na+ ion?

Electronic configuration of $Na^+$ ion is $1s^2,2s^2,2p^6,3s^0$. I have noticed usually , we take spin quantum number as +1/2 first & then -1/2. So , like for the above Q:It is for first 3e=+1/2 &...
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2 votes
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Average distance of 1s electron from nucleus in He⁺ ion

What would be the average value of $r$, i.e. $\langle r\rangle$, in the $\mathrm{1s}$ orbital of $\ce{He+}?$ $$ \text{a}.~\frac{3}{2}a_0 \qquad \text{b}.~\frac{3}{4}a_0 \qquad \text{c}.~3a_0 \qquad ...
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When people say "The energy of an orbital depends on its ℓ value due to screening effect" , what is screening what?

My book says: Both the attractive and repulsive interactions depend upon the shell and shape of the orbital in which the electron is present. For example electrons present in spherical shaped, s ...
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Energy levels of carbon and selection rules

Here is an atomic physics problem I am trying to solve: The carbon ground state is $[He](2s)^2(2p)^2$. Suppose to excite an electron to the configuration $[He](2s)^2(2p)(3s)$. The spectroscopic terms ...
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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 ...
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What happens inside the orbital when energy provided to electron is not sufficient for it to change orbitals? [closed]

While studying the chapter called Atomic Structure, we were introduced with Bohr's model of an Atom. Even though not all of his postulates were right, I believe some were. A doubt arose in the ...
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Do degenerate states have exchange energy?

I have read that exchange energy exists between non-degenerate levels $1s$ and $2s$ or between $1s$ and $2p_x$ in the Helium atom in the first excited level: $$K_s = \left< 1s(1)2s(2)|H'|1s(2)2s(1) ...
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1 vote
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Shielding effect is not constant across a period [closed]

Shielding effect stays constant across a period because number of inner electrons stays the same. Well, that's not true. It only works for the period =1,2,3 but in period 4, the number of inner ...
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-3 votes
1 answer
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atomic structure - why only hydrogen be separately written in periodic table [duplicate]

The other exception is hydrogen. It has only one s-electron and hence can be placed in group 1 (alkali metals). It can also gain an electron to achieve a noble gas arrangement and hence it can behave ...
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5 votes
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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 ...
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3 votes
3 answers
112 views

Where are orbitals located in an atom? [closed]

I am having trouble understanding what are the orbitals. Till now what I have understood, I have depicted in this diagram. Is the diagram correct?? If not, what should be the corrections?
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Why are HOMO and LUMO energies invariant under spin-flip?

Atomic theory says singlet and triplet energies for the same orbital differ because of exchange interaction. However, molecular orbital (MO) theory describes the energy between the HOMO (highest ...
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A better understanding of the screening effect and how it works?

What I am taught- Inner shell electrons shield the outermost electrons from the attraction of nucleus. More closer the inner shell is to the nucleus, more its shielding effect. thus $n_s > n_p > ...
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2 votes
3 answers
2k views

Which atom is the smallest atom?

Is hydrogen or helium the smallest atom? My teacher said that the smallest atom is the helium atom, but I think that the smallest atom is the hydrogen atom. It has a single electron and a single ...
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0 votes
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76 views

The necessary energy required to ionize 1g of potasium in its fundamental state if the ionization energy is given

The energy of ionization of the potassium is $\pu{6.94\cdot 10^{-19} J/atom}.$ Find the necessary energy to ionize $\pu{1 g}$ of potasium that is found on its fundamental state. Attempt. I really ...
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Comparing average radius of subshells for multielectron atoms

I recently came across a question comparing the average radius of subshells. A search on the internet gave the following result for single electron atoms: $$\langle r\rangle_{n,\,l}=\frac{a_0 n^2 \...
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respective posistion of d and p orbitals in a multielectronic species

we write the electronic configuration of atoms as [noble gas core]4s2 3d10.that is that due to energy considerations(aufbau principle) in multielectronic species. what i want to know is whether the 4s ...
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1 vote
1 answer
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Comparing strengths of σ-bonds formed by $\mathrm d_{z^2}$ and $\mathrm p_z$ orbitals

According to my professor $\mathrm d_{z^2}–\mathrm d_{z^2}$ σ-bond is stronger than $\mathrm p_z–\mathrm p_z$ σ-bond as the extent of overlapping is greater in $\mathrm d_{z^2}–\mathrm d_{z^2}$ ...
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3 votes
1 answer
194 views

Lother Mayer curve

While studying about atomic trends, I encountered the Lothar Meyer curve: Similar graph found on internet If the covalent radius decreases across a period, why is the graph of atomic volume ...
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-1 votes
1 answer
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Which electron should be considered the last one?

Today I came across a problem which asked some quantum number informations regarding the last electron of Zinc. Now as far as I have studied 4s subshell is filled in preference to 3d subshell bcos of ...
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1 vote
0 answers
37 views

Calculating electrons emitted when quantum yield is given

In a problem, the wavelength $\lambda$ of a monochromatic light, power $P$ of the source, and work function $\phi$ of the metal on which the light is shown is given. Quantum yield is $n$. I have to ...
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2 votes
1 answer
609 views

What is the average distance between electron 'shells' in an atom? Or between the innermost shell and the nucleus? [closed]

Somehow, I've never come across any mention of the actual, physical distances between, say the 1s and 2s shells in an atom, whether large or small.... I know that p, d and f (and g?) shells are oddly ...
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1 vote
1 answer
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How is most probable radius in quantum mechanical model equal to Bohr's radius in hydrogen atom

Most probable radius in 1s orbital for hydrogen electron is $\pu{0.529E-10 m}$ which is Bohr radius. But energy of electron in hydrogen atom is proportional to mean radial distance in atom. In this ...
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-5 votes
2 answers
270 views

What would happen if the alpha particles directly hit the electrons in the gold foil in Rutherford's experiment? [closed]

What would happen if the alpha particles directly hit the electrons in the gold foil in Rutherford's experiment? Would it get ionized or is there no probability of such a thing happening ?
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1 answer
536 views

What is the radial probability distribution function and what is its significance? [duplicate]

Below I have given three graphs for the $\ce{1s}$ orbital. $R(r)$ is the radial part of the wave function of the electron. $R^2(r)$ is the radial part of the wave function of the electron multiplied ...
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6 votes
2 answers
659 views

Why is potassium less dense than sodium?

Potassium has a density of $\pu{0.86g/cm3}$ and sodium has a density of $\pu{0.97g/cm3}$,even though potassium is below sodium and one might expect the alkali metals to exhibit monotonously increasing ...
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1 vote
0 answers
42 views

molecular orbital theory and crystal field theory confusions

I am a high school student and I am very confused in Molecular orbital theory, it says that when two orbitals overlaps in the same phase, they form antibonding orbitals and when they overlap in ...
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2 votes
2 answers
196 views

What does Bohr's model predict if the mass of an electron becomes 10 times its actual mass? [closed]

If the mass of an electron becomes 10 times its actual mass, which of the following statements is correct regarding Bohr's model: Velocity of electron increases by 10 times. Orbit radius decreases by ...
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-3 votes
2 answers
60 views

Will a Crooke's Tube stop working after sometime? [closed]

A Crooke's Tube is a cold-cathode tube, wherein electrons are released from the cathode when ionised gas particles strike it with speed. Following a chain reaction, other gas particles also get ...
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4 votes
1 answer
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Practical to measure topography of a large area (mm-scale) with scanning probe microscopy (SPM)?

I'm currently very new to nanotechnology. I do understand that it is possible to achieve an excellent topography image of a sample by SPM. However, is it possible to do SPM over a large area (for ...
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-5 votes
1 answer
41 views

what is the use of finding out the radius of an atom [closed]

I happen to come across this, but what is the radius of an atom, velocity, KE, PE, etc.. actually used for? like the formula r=0.529n^2/z and so on
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3 votes
1 answer
297 views

Why is strontium(II) ion bigger than krypton atom?

$\ce{Sr^2+}$ is exactly the same as $\ce{Kr}$, in terms of electrons and orbitals. The only difference between the two, is that $\ce{Sr^2+}$ has a couple of extra protons in the nucleus (and probably ...
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Why are electrons filled in fourth shell before the third shell is filled?

I am a beginner and am learning about atomic structure and I am getting confusions regarding the aufbau principle. It is said that the electrons will be filled first in lowest available energy level. ...
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3 votes
1 answer
80 views

Is the effective nuclear charge only defined for valence electrons?

I've just been taught about the effective nuclear charge and screening effect in school. I'd like to ask and confirm if the effective nuclear charge is only defined for valence electrons. If not then ...
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6 votes
1 answer
161 views

Basics of wave-mechanical model of atom

Why is it that for the $\mathrm{d}$ subshell we have $\ \ \mathrm{d}_{xy}, \ \ \mathrm{d}_{yz}, \ \ \mathrm{d}_{xz}, \ \ \mathrm{d}_{x^{2}-y^{2}},$ and $\mathrm{d}_{z^{2}}$ orbitals only? Why aren't ...
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1 vote
1 answer
113 views

Excitation of electron in Niels Bohr's atomic model

Professor taught us that an electron gains or looses only those energies which are equal to difference in two energy levels. That is $E_1 + \Delta E = E_2$ or $E_1 + \Delta E = E_3.$ What if we give, ...
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