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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Correct Electron Configuration of Ni-28

I have seen two electron configurations for $\ce{_{28}Ni}$ in my chemistry textbook: $$[\ce{Ar}]~3d^8~4s^2$$ $$[\ce{Ar}]~3d^9~4s^1$$ Which of those is ACTUALLY the correct one (in real life, reality)? ...
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43 views

Why 4s lose electron to 3d? [duplicate]

In chromium and copper, the are the configuration fill up like $$\mathrm{3d^5 4s^1}$$ but not $\mathrm{4s}$ first as it has lower energy level. and why only these 2 elements.
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47 views

Each electron shell can hold up to 2n² electrons. Is there a geometric reason for this?

It seems such a simple formula, that each electron shell can hold in principle two times a square number. I imagine there must be a geometrical reason for this, that's to do with the way electron ...
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40 views

Are bond orders always the same in isoelectronic diatomic species?

In my textbook of chemistry it is written that: In the Lewis description of covalent bond, the Bond order is given by the number of bonds between the two atoms of a molecule. ... ...
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13 views

electronic configuration of lanthinide series [duplicate]

Why does the 57th electron enter the $5d$ subshell in lanthanum, shouldn't it should enter the $4f$ subshell according to the Aufbau rule? Also in thorium, the 89th and 90th electrons enter ...
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35 views

Why Cr(2+) stronger reducing agent than Fe(2+) in water?

According to me $\ce{Fe^{2+}}$ should be a better reducing agent because $\ce{Fe^{2+}}$ after getting oxidized will get a stable $d^5$ configuration and $\ce{Cr^{2+}}$ will get a $d^3$ configuration. ...
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111 views

What is the difference between the KLMN and SPDF methods of finding electronic configuration?

I've always been puzzled by this because my teachers happen to use only the KLMN method, but what is the difference between the KLMN and SPDF methods of finding electronic configuration?
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134 views

Why do 3d orbitals have lesser energy than 4s orbitals in transition metals? [duplicate]

This is quoted from Jim Clark's Chemguide For reasons which are too complicated to go into at this level, once you get to scandium, the energy of the 3d orbitals becomes slightly less than that of ...
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59 views

Why does an element's chemical properties rely only on its valence electrons and not on anything else?

I understand that elements use their valence electrons for their reactions and whatnot, and that the whole idea of the electron-dot structure is all about valence electrons. But why can't the other ...
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53 views

Calculate the valence of Fe2O3 [duplicate]

$$\ce{FeO}$$ Is called "Iron(II) oxide ". $$\ce{Fe_2O_3}$$ Is called "Iron(III) oxide ". The number in the parenthesis is "Valence" of the substance. Frankly, I don't know how to calculate such ...
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66 views

Calculating valence of oxides

Learning about Oxides. Basically when oxygen is combined with a metal. $$\ce{FeO}$$ This is called "Iron Oxide (II)" according to my book. Apparently, the II represents the valence. But how come? ...
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28 views

My text seems to say that the high(est) energy orbitals are not valence orbitals - everything else says otherwise. What's true?

A paragraph in my text reads Bonding involves the valence orbitals almost exclusively because these orbitals have the appropriate energies to interact strongly. Examine the electron energy-level ...
6
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302 views

Which relatively simple molecules violate the octet rule?

I'm learning how to draw Lewis diagrams. Everything I've read emphasizes the octet rule. However, to the best of my knowledge, that rule only applies to elements in the first three periods. On our ...
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59 views

Why are electron configurations more stable when there are 8 electrons in the outer shell?

In this video on Khan Academy, Sal remarks that 'all atoms envy the noble gases, which are the most stable because they have eight electrons in their outer shell'. I can't think of much of a reason ...
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1answer
45 views

Do I understand why the atomic radius of Kr is smaller than the atomic radius of K?

Potassium comprises 19 protons and 18 core electrons. Those electrons screen 18 protons worth of Coulomb force. Therefore, there is one proton worth of Coulomb force attracting the valence electron of ...
6
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1answer
182 views

Why doesn't gold corrode? [duplicate]

As the electronic configuration of gold is [Kr] $4d^{10} 4f^{14} 5s^2 5p^6 5d^{10} 6s^1$, the valence shell is not completely full. Why doesn't gold corrode?
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Can an atom bond with more than 8 other atoms?

Is it possible for an atom to bond with 8 other elements (same or other type)? If yes, then please give some examples. If no, then what could be the possible reason for it? Update + Edit: My question ...
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44 views

Reading number of outer shell electrons and other properties from periodic table?

How can one read from the periodic table the number of outer shell electrons that an atom has, to predict how these atoms will make bonds with other atoms? For example to see that hydrogen ($\ce{H}$) ...
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29 views

Stability of half and fully filled orbitals [duplicate]

1) My textbook tells me that chromium's electronic configuration is $\ce{[Ar]}\space 3d^5 4s^1$ instead of $\ce{[Ar]} \space 3d^4 4s^2$, as fully filled and half filled orbitals have more stability. ...
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1answer
61 views

How are electronic configurations determined experimentally?

Despite the ubiquitous usefulness of electronic configurations (of elements) in explaining their behavious I have not been able to find out exactly how the configurations are determined. Is there ...
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210 views

Energy of photons emitted by de-excitation of electrons

When an electron of an atom returns from an excited state to the ground state, it emits energy in the form of a photon. How does the change in energy level compare to the energy of the emitted photon? ...
3
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709 views

what is SPDF configuration?

Recently in my chemistry classes the teacher spoke about SPDF configuration and then said that we'll be taught about it in higher classes. But I'm sorta curious to know that what is SPDF ...
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41 views

How to find the highest and lowest oxidation state of transitional metal

My teacher taught me the formulas 'nS' and 'nS+(n-1)d' to find the highest and lowest oxidation state of transition elements. He gave the example of $\ce{Mn}$ and showed that the numbers were +2 and ...
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34 views

Azimuthal Quantum Numbers [duplicate]

Why do azimuthal quantum numbers have a value lesser than Principal Quantum number. example- if n=1 it will have subshell "s" as 0
4
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1answer
34 views

Is it possible to predict the lines in the atomic emission spectrum of Na?

The atomic emission spectrum for sodium ($\ce{Na}$) is completely dominated by a line in the range of yellow, about $590~\mathrm{nm}$ (to be more precise, it's a doublet). Here is how it looks like: ...
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21 views

Is one electron spin preferred over the other in filling of orbitals? [duplicate]

When filling an orbital diagram of an atom, usually the up-spin is filled first and then the down-spin. For example, for Nitrogen, we have : But in a model in which up-spin electron is preferred ...
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188 views

Hypervalency and the octet rule

I realize that the octet rule is more a suggestion than a rule, and that it applies mainly to non-transition metal compounds. Still, compounds that don't have an octet, like $\ce{BH3}$, tend to ...
2
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1answer
42 views

MO for $N_2^{2-}$

Could someone please show me the MO diagram for $\ce{N_2^{2-}}$? What I did was since N has 5 valence $\ce{e^{-}}$, then $\ce{N_2}$ must have 10, and $\ce{N_2^{2-}}$ must have 12. And $\ce{N}$ has $s$ ...
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44 views

Atomic number $Z$

If electrons were spin-$\frac {3}{2}$ instead of spin-$\frac {1}{2}$ , what would be the atomic number $Z$ for the first noble gas ?
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54 views

How does radiation facilitate the formation of tetravalent iron?

In reading the article abstract What Oxidation State of Iron Determines the Amethyst Colour?, the author states that in regards to the gemstone amethyst, from clear quartz: The crystal was ...
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104 views

How many electrons does each shell hold?

why some times 2nd shell onward it can hold 8 electrons and other times it is like they can hold K2 L8 M18 N32? when do i have to use first method(K2 L8 M8 N8) and when to use second method (k2 L8 ...
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Quantum Numbers and Ions

How do quantum numbers change for ions? A sample question: Give the set of four quantum numbers that could represent the electron lost to form the Rb ION from the Rb atom. The answer given is n=5; ...
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Why does this reaction take place in terms of electronic structure?

I need to know, in terms of electronic charge - the electrophiles and nucleophiles involved - how the electronegativity of the potassium and hydrogen atoms alongside the hydroxide and H+ ions result ...
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107 views

Second ionization potential of Gadolinium

I notice that Gd has a second ionization potential which is significantly higher than would be expected from the general trend in the lanthanides (see this paper p. 945 for a graph). What is the ...
3
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2answers
162 views

What is the electronic configuration of Fe(II) ion?

The electronic configuration of Fe is 1s2 2s2 2p6 3s2 3p6 4s2 3d6. So after removing two electrons the configuration becomes: 1s2 2s2 2p6 3s2 3p6 3d6 But why cant the electrons rearrange themselves ...
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124 views

A unique demo for singlet oxygen?

I have long known that mixing bleach and peroxide produces oxygen gas: $$\ce{NaOCl + H2O2 -> O2 + H2O + NaCl}$$ However I only recently learned that the specific form of oxygen produced by the ...
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76 views

abbreviations in electronic configurations

I am teaching my students how to write the electronic configuration of the elements of the periodic table. Thus, following the rules on how to fill the orbitals, the electronic configuration of iron ...
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33 views

degeneracy and Mendeleev table [closed]

A very basic question. When we construct Mendeleev table we can think of adding one electron at a time, filling one by one the electronic states, that are numbered by well known quantum numbers (using ...
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1answer
230 views

Hybridization of the oxygen in furan?

I fail to understand why the hybridization of oxygen in furan is $\ce{sp^2}$. I think that since there are 2 bond pairs and two lone pairs so it should be $\ce{sp^3}$ hybridized? Is it to do with the ...
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sp² hybridized orbital

I do not understand why and how an atom with $\ce{sp^2}$ hybridization has only one p orbital?? For example in pyridine why is the lone pair of nitrogen not counted as a pi electron.
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37 views

What does this property of transition metals mean? [duplicate]

what does it mean: "Transition metals either have incompletely filled d subshells or readily give rise to cations that have incompletely filled d subshells. I don't understand the portion starting ...
2
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1answer
120 views

Electron Configuration of an element with no. of electrons > 18

Let's say that we have an element, say $\ce{Ca}$. According to law, the last shell should contain only upto 8 e-. Hence, electronic configuration of $\ce{Ca}$ would be 2,8,8,2. But, according to the ...
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117 views

Why does the electron configuration for some elements not follow the diagonal rule?

I'm doing a high-school assignment, and I came across a question that I didn't quite understand. Explain how the electron configurations for the following elements do not follow the diagonal ...
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2answers
85 views

Why is it that weak bases usually contain a Nitrogen?

Why do weak bases usually contain a nitrogen, I know there are two electrons on top for a bond of H but why is it mostly nitrogen? I know there are other elemental bases too but why do I keep seeing ...
3
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1answer
68 views

Is it possible to calculate atomic radius with electron configuration?

I need to know whether is it possible to calculate the atomic radius according to the number of electrons and electron configuration. Or is there any way to calculate the atomic radius using common ...
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38 views

Why are d-orbitals required/used for hypervalent molecules (where the central atom has expanded its octet) [duplicate]

Period 2 elements like carbon, oxygen and nitrogen cannot expand their octet because they cannot make use of d orbitals in that energy level (they don't exist). However, period 3 elements like sulfur ...
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77 views

Why the second ionization energy of helium is greater than the first? [closed]

maybe because the first electron has a lower energy. Why does this happen?
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86 views

What is the usage of orbitals more complex than f orbitals?

Every high school learner, in each corner of the world, faces the lesson History of Atom during his courses, just as I did. We learned about s,p,d and f orbitals, though there were no signs of ...
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106 views

How to find the possible valence states of elements in the lower end of the d block and the f block?

For silver, why don't the electrons in the 4d orbital move to the 5p orbital? Is it possible for any elements to move their electrons between $n$d and $(n+1)$p orbitals? When the f orbital is ...
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41 views

Why don't electrons pair up in an oxygen radical?

In an oxygen radical (produced by the break down of O3 for instance), there are 2 unpaired electrons in the outermost subshell which make the molecule unstable. Why don't these electrons pair up which ...