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### 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 ...
21k views

### Why does potassium have the electronic configuration of 2.8.8.1? [duplicate]

We all know that potassium, the 19th element on the periodic table has the electronic configuration of 2.8.8.1. However, why not 2.8.9? In the element scandium, it has the electronic configuration ...
1k views

### What is the correct order of subshell energies? [duplicate]

I was taught in high school that the order is given by the Aufbau Principle: 1s>2s>2p>3s>3p>4s>3d>4p>5s>4d>5p>6s>4f>5d>6p... Why is the 3d subshell higher in energy than the 4s subshell if it is in a ...
326 views

### Why is the valency of the Calcium (Ca) Bohr model, set to 2 electrons, instead of 1 electron for stability? [duplicate]

This is an Ascii table for the elements on the 4th period (row) of the periodic table, and distribution of electrons in each orbit. ...
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### Why do PES graphs list 4s after 3d? [duplicate]

Coming straight off of some electron configuration worksheets, our teacher started to teach us how to read photoelectron spectroscopy (PES) graphs and I'm having a bit of trouble with the two. During ...
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### Electron shells and subshells energies [duplicate]

According to what i learned in university, the energy of orbitals increases when the principal quantum number n increases. Also, in a given shell, s orbitals have lower energy than p orbitals which ...
30k views

### 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 ...
1k views

### While filling electrons, we follow Aufbau principle, but not while removing them. Why is this so?

I recently came across a question Why is the vanadium(3+) ion paramagnetic?, where the asker is wondering how $\ce{V^{3+}}$ is paramagnetic (he used Aufbau in reverse to remove the electrons), while ...
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### Why is the 5d orbital instead of the 4f orbital filled in lanthanum?

For orbitals with the same value of $n + l$ (e.g. the $\mathrm{3d}$ and $\mathrm{4p}$ orbitals), we usually expect the orbital with the lower value of $n$ to be filled earlier. Hence, for example, the ...
24k views

### Electron orbital diagram of vanadium [duplicate]

I am learning about electron configurations and I came across the "exceptions" of $\ce{Cr}$ and $\ce{Cu}$ where electrons actually half fill the $\mathrm d$ orbitals instead of the expected $\mathrm s$...
8k views

### Why does Ruthenium only have one electron in its 5s orbital in the neutral oxidation state?

So recently I have undertaken some research with some organometallic chemistry involved, specifically regarding that of ruthenium-aryl compounds. Trying to understand the chemistry of the central ...
2k views

### Why do the d suborbitals start at 3d instead of 4d?

Why do the suborbitals for d start at 3 instead of four? It is in the fourth row on the periodic table and all other suborbitals start according to the row on which they are located except for d. Why ...
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### Electron configurations for d-block and p-block

Question 1: Why is it that when you get to the transition metals (or the d-block), the energy of the $\ce{3d}$ orbitals becomes slightly less than that of $\ce{4s}$, making $\ce{4s}$ have the ...