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-2 votes
1 answer
81 views

Why do we only use the principal quantum number to calculate the energy of an electron in an H atom? [duplicate]

According to my high school textbook the energy of an electron in a hydrogen atom is $E = -13.6/n^2~\pu{eV}$, where $n$ is the principal quantum number of the orbital in which the electron is present. ...
0 votes
1 answer
53 views

Perforated Cathode in Anode Ray Experiment

While studying about the anode ray experiment (E. Goldstein), I had a doubt pop up in my head. In the experiment, a perforated cathode has been used. What is the exact reason behind that? Upon ...
0 votes
2 answers
126 views

What does "predicted" mean in an electronic configuration?

I've noticed the term "(predicted)" appearing at the end of electron configurations for heavier elements. Could you explain what it signifies and the reason behind it? I haven't been able to ...
0 votes
0 answers
37 views

The existence of a principal quantum level or energy shell after the loss of an electron from the outer shell of an atom

With the loss of an electron from $\ce{Li}$ ($\mathrm{1s^2\ 2s^1}$), we get $\ce{Li+}$ ($\mathrm{1s^2}$), then the 2nd shell where the electron had been revolving in $\ce{Li}$ will get disappeared or ...
3 votes
1 answer
427 views

If charge is quantised, how can It delocalize?

As I was trying to understand resonance, I got to know that it was imaginary phenomenon and it is just a tool to explain mechanisms and structures that are unexplained by Lewis dot structures or ...
0 votes
0 answers
67 views

Can someone elaborate what it means when its said that electron shells do not exist in multi electron systems?

I'm an undergraduate student in chemistry. I'm trying to grapple with all the new stuff we're learning and making sense of it. Now I want to know if electron shells really "exist" in multi ...
-2 votes
1 answer
127 views

How can Planck’s equation and the wave equation simultaneously coexist with contradicting each other? [closed]

The equations: E=hf (Planck’s equation, where E is the energy, h is the Planck’s constant and f is the frequency) and V=fλ (where v is the speed (in a vacuum), f is frequency and λ is the wavelength) ...
0 votes
1 answer
129 views

Finding excited stage of electron from its potential energy

The potential energy of an electron in the hydrogen atom is $\pu{-6.8 eV}.$ Indicate the excited stage in which electron is present. Total energy would be equal to $\pu{-3.4 eV}.$ I used the formula $...
0 votes
1 answer
5k views

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 ...
1 vote
1 answer
60 views

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 ...
2 votes
0 answers
249 views

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 &...
1 vote
0 answers
68 views

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 ...
1 vote
0 answers
361 views

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 ...
3 votes
3 answers
7k 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 ...
4 votes
0 answers
733 views

Did JJ Thomson know about Eugen Goldstein’s experiment discovering canal rays?

We learn that JJ Thomson discovered the electron in 1897. Several years EARLIER in 1886, Eugen Goldstein performs the same experiment but with the anode and cathode switched to produce positively ...

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