Questions tagged [electronic-configuration]

In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals.

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How can we determine an element's number of electrons with a magnetic quantum number of zero (ml=0)?

I know how to find the number of electrons in an element, but I'm not sure if there's any formula to determine an element's number of electrons with a magnetic quantum number of zero (ml=0). For ...
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Which is more stable and why: a half-filled s subshell or a half-filled p subshell? [closed]

Is $\mathrm{(1s)^2 (2s)^2 (2p)^6 (3s)^1}$ or $\mathrm{(1s)^2 (2s)^2 (2p)^3}$ more stable? Which has larger ionization enthalpy?
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Noble Gases are stable [duplicate]

One of the most important concepts in chemical bonding at least with valence bond theory is that every element wants to have an electron configuration of a noble gas. But why is that? If we have the ...
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Alkali metals chemistry [closed]

Ok my understanding of the electronic structure of atoms could be wrong but this is why I don't understand:Why alkali metals are so much electropositive. Some high school professor in chemistry would ...
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What is the number of unpaired electrons in (Fe(H2O)5NO)2+? [closed]

Given the fact that $\ce{NO+}$ is a strong field ligand and iron is in the +1 oxidation state, the valence orbitals of $\ce{Fe+}$ must undergo rearrangement from $\mathrm{3d^{6}4s^{1}}$ to $\mathrm{3d^...
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What is the meaning of the J value in term symbols [closed]

I understand how to work out the J values of term symbols. e.g. a d1 configuration gives J values of 5/2 and 3/2. resulting in 2D 3/2 However I dont understand the meaning of it, and why it arises.
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I have got a doubt regarding the electronic configuration. Can an element have a third energy shell without completing the second energy shell?

In the question an electronic configuration diagram is given. It has three shells, but the first shell has only one electron, and the second has six. The third energy shell has five. Out of the shells,...
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Ground state term symbol for Cerium (Ce)

I need to calculate the term symbol of the ground state configuration of Cerium. The electron configuration is: $[Xe] 4f^1 5d^1 6s^2$ Since the d and f electrons are in different subshelles, they are ...
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Temperature dependence of emission lines from gases, for example, neon

Emission lines from Ne are frequently used as wavelength standards in spectroscopy. Reading around Wikipedia, I found about the Paschen law regarding the voltage required to start a discharge. My ...
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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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Check My Beginner's Guide to Shells, Energy Levels, Subshells, and Orbitals [closed]

I am a beginner trying to summarize what I've learned about: Shells Energy Levels Subshells and Orbitals all at the high school level. Unlike related threads, I'm going to try to: Define each word ...
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Difference in a array of probability density plots for the electron in its lowest-energy states of Hydrgen atom [closed]

Dynamic Periodic Table If you visit Dynamic Peridic Table, You will notice that for n=4 l=3,2 m=0,0, and n=2,l=1, m=0 there is a difference in the probability density plots for electron in its ...
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Empirical Evidence and Assignment of Orbital Energies (Electron Filling)

I see a lot of questions on electron configurations from students at various levels here. Students mechanically remember how to fill orbitals and sorry to say many teachers do the same. Not a single ...
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How many valence electrons do elements in the d block have?

I just noticed that on the periodic table it doesn't say how many valence electrons there are for each column in the d block. How do I find out how many valence electrons elements in the d block have?...
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Size consistency in computational chemisty methods

I am looking for a clear answer that would explain what exactly size consistency is, why configuration interaction (CI) is not size consistent and how this leads to errors when using CI for large ...
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Why aren't Boron and Aluminium assigned to group 3 of periodic table? What determines the group? [closed]

I've been curious about this 3D representation of the periodic table "Mendeleev's Flower" and was trying to study it, wondering if it reveals any regularities that are not obvious from classic ...
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The violation of a certain rule or principle in the following electronic configuration

I'm to find the violation of a certain rule or principle in the following electronic configuration: $$\ce{1s^2 2s^2 2p^1_x 2p^0_y 2p^0_z}$$ $n+l$ rule is not violated because: for $\ce{1s^2}$, $n+l=...
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Electron pairing in atoms

A question asks: This question refers to isolated gaseous atoms. In which atom are all electrons paired? Ba, Br, S or Si? I thought it was Ba as its electron configuration is [Xe] 6s2. However, ...
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How electron configuration is related to the oxidation state of an element such as sulphur and can this be extended for elements in other blocks? [closed]

The question arises from trying to get where does the values of $-2$, $0$, $+2$, $+4$ and $+6$ from the electron configuration. The electron configuration for sulphur $(Z=16)$ is $[Ne]3s^23p^4$. It ...
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Does it exist a transgression to Hund's rule of maximum multiplicity principle in this given electron box notation?

The following question arises from a set of statements from which I'm asked to state whether they are true or false. This is as follows: Indicate which of the following statements are true or ...
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Density of d-block elements

Something that confuses me slightly is the trends in density when comparing periods 4, 5, and 6 in the d-block. Looking at periods 5 and 6, the density peaks at group 8, with ruthenium and osmium, ...
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Confusion in half filled or full filled electronic configuration

At the end of electronic configuration, we were taught that, electron orbitals are most stable when they are either fully filled or half filled. E.g., the final valence configuration of chromium is $\...
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If copper has 2 valance electrons and sulfur 6, why don't they bind in pairs?

Simple question, the average neutral copper atom has 2 valance electrons, and sulfur 6. Wouldn't the two electrons jump from copper and bind to sulfide? The empirical formula is: $\ce{Cu + S -> ...
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Two different electronic configurations for cerium

Depending on the textbook there are two different electronic configurations stated for cerium. On the one hand $$[\ce{Xe}]\mathrm{4f^15d^16s^2}\quad$$ and on the other hand $$[\ce{Xe}]\mathrm{4f^...
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Why is the number of covalent bounds typically formed by an element equal to 8 minus the group number? [closed]

Why would the number of covalent bounds typically formed by an element equal to 8 minus the group number? E.g for C, we have 8-4 bonds, for Cl, 8-7 bonds
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Where does the 9th electron go in a N=O bond?

In the first resonating structure you can see 5 unpaired electrons and 4 shared electrons on nitrogen, then isn't this a extended octet? If it is so, then in which orbital that 9th electron is ...
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Reconciling electron configuration and valence electron distribution over separate energy levels in energy band theory [duplicate]

The electron configuration of a Silicon atom in its ground state is $\ce{1s^2 2s^2 2p^2 3s^2 3p^2}$, or equivalently, $\ce{[Ne] 3s^2 3p^2}$. When looking at the energy-level scheme of a silicon atom, ...
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Why does 2+ oxidation state become more stable relative to 3+ oxidation state for first row of transition metals? [duplicate]

I viewed an image showing all the possible oxidation states of each element in the first row of transition metals, and the main oxidation states highlighted in a different colour. I noticed all ...
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Direction of electron density in p orbitals

$\mathrm{s}$ orbitals are spherically symmetric while $\mathrm{p}$ orbitals are not. For Boron, the electronic configuration is $\mathrm{1s^2 2s^2 2p^1}$. In which p orbital does the most energetic ...
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Why does Boron only need 6 valence electrons unlike the standard 8?

So I was a bit confused. Hydrogen and Boron seem to be the only outliers to the octet rule. Hydrogen makes sense because it has only one shell and 2 electrons complete its shell. Boron's configuration,...
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On the meaning of distinguishability, and wavefunctions for 3 electron atoms

In a 2-electron atom at lowest energy, the $(1s)^2$ is occupied and the electronic wave-function must satisfy anti-symmetry requirements in the particle coordinates, as the spatial wave function is ...
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Why does period 3 of the periodic table contain 8 elements instead of 18?

Period 1 of the periodic table contains 2 elements ($1s^1$ and $1s^2$). Period 2 contains 8 elements ($2s^1$, $2s^2$, $2p^1$, $2p^3$, ..., $2p^6$). By the same argument, period 3 might contain 18 ...
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Why is nitronium ion an electrophile?

I have learnt that the species which have vacant orbital(s) are called electrophiles. But in this case, the nitrogen has a complete octet. The positively charged nitrogen ion has a valency of 4, of ...
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Is electron density a good measure of similarity between molecules?

I am looking for a good similarity measure between molecules in order to use it with machine learning algorithms. I found a paper, Carbó, R., Leyda, L. and Arnau, M. (1980), How similar is a molecule ...
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Why is the vanadium(3+) ion paramagnetic?

I know that the electron configuration of vanadium is $[\ce{Ar}]\mathrm{4s^2 3d^3}$. None of the electrons in the 3d subshell are paired. Once it loses these three electrons, shouldn't the remainder ...
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Why do elements in columns 6 and 11 assume 'abnormal' electron configurations?

When I look around for why copper and chromium only have one electron in their outermost s orbital and 5/10 in their outermost d orbital, I'm bombarded with the fact that they are more stable with a ...
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What is the maximum number of electrons that can be found in an atom when its last electron has the following quantum numbers?

The question is as follows: What is the maximum number of electrons that can be found in an atom when its last electron has the following quantum numbers: $n=4, m_{l}=+3$ Since $m_{l}=+3$ I know ...
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Why does iron have an abnormally high ionization energy?

Along a period the ionization energy should increase because the atomic number is increasing, but there is negligible increase in shielding. However, $\mathrm{IE}_\ce{Mn} < \mathrm{IE}_\ce{Fe} > ...
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Is the nickel an exceptions to the electron configuration? [duplicate]

the electron config. is this 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8 can the 2 electrons in the 4s be donated to the 3d to make them diamagnetic?
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Intuition for why effective nuclear charge increases down a column

My textbook (Chemistry the Central Science, edition 12, Brown et al.) says that effective nuclear charge increases down a column. Indeed, this is consistent with the values provided by Clementi in the ...
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Why $ns^2np^6$configuration so stable? [duplicate]

In my chemistry textbook it is said that noble gases have stable configuration because they have achieved the maximum outermost shell configuration, which corresponds to the $ns^2np^6$ configuration. ...
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What do the subscripts 1/2 and 3/2 for the p-orbitals refer to?

What does $p_{1/2}$ and $p_{3/2}$ mean when referring to electron configuration? I've seen sub shells and I'm assuming it has something to do with spin. I am asking this in regard to the $8p_{1/2}$ ...
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Why group 13 elements don't show +2 as their major oxidation state?

These are the things I understand: 1) Group-13 elements show +1 and +3 as their major oxidation states(OS). 2) The general configuration of G-13 elements is $ns^2$ $np^1$. 3) In the ...
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Exceptions to the Madelung rule for electronic configurations

The electronic configuration of platinum is $$\mathrm{[Xe] 4f^{14} 5d^9 6s^1}$$ and not $\mathrm{[Xe] 4f^{14} 5d^{10} 6s^0}$ or $\mathrm{[Xe] 4f^{14} 5d^8 6s^2}$. I see this question has already ...
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How can a methyl cation exist without 8 valence electrons

So far I have been taught that everything wants to achieve noble gas configuration - 8 electrons in the outer shell. I came across a methyl cation. Which contains a positive carbon, no lone pairs and ...
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Shortcut method to find atomic term symbols ignoring the spin orbit coupling

Is there any shortcut method by which we can find the atomic term symbols ignoring the spin-orbit coupling, i.e. ignoring the values of J. For instance, when writing the d-d transitions for any ...
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Diamagnetic vs Paramagnetic

As far as I know, to know whether a substance is paramagnetic or diamagnetic, we check if that particular species has got unpaired electron or not. But my textbook lists- Examples of Diamagnetic ...
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A Question on the Role of Triplet Oxygen in the Formation of Artemisinin

It is observed that whereas singlet oxygen is required for an ene reaction with an alkene to give an allyic hydroperoxide, triplet oxygen will react similarly with an enol to give an alpha-hydroperoxy ...
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Why is Thorium (At. no. 90) an f-block element at all?

Being an exception of the Aufbau principle, Thorium has an electronic configuration of $\ce{[Rn]}\mathrm{7s^25f^06d^2}$ instead of the expected $\ce{[Rn]}\mathrm{7s^2 5f^2 6d^0}$. Two other elements, ...
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Why are sulfur trioxide and nitrate not isoelectronic, even though both have the same number of outer electrons?

Though $\ce{SO3}$ has the same number of outer electrons as $\ce{NO3-}$, the two are not isoelectronic. This statement is from JD Lee, but I could not understand why is he calling these two molecules ...

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