All Questions
49
questions
0
votes
1
answer
138
views
Mg2+ ion formation [duplicate]
Why does Mg not form a Mg+1 ion, even though its second ionization energy is much higher than the first ionization energy?
(I know that an ion should resemble the noble gas closest to the element from ...
- 77
0
votes
1
answer
95
views
How to compute solvent reorganization energy in Marcus' non-equilibrium approach?
I try to solve the following equations for some system solvated in the water. The goal is to obtain value in kcal/mol. Unfortunately, I cannot reach the desired output. May someone help me?
The ...
- 103
-2
votes
1
answer
48
views
Where does the ionisation energy for a reaction to take place comes from? [closed]
Can anyone tell me exactly what happens during a chemical reaction in terms of ionisation energy? I know that during a reaction there is an exchange of electrons (except for those where electrons are ...
-1
votes
1
answer
50
views
Electron energy shells/ levels
Essentially, I am told electron shell closest to the nucleus is the lowest energy level and subsequent shells have higher energy (I.e. those further from the nucleus).
But..... electrons in the ...
-4
votes
1
answer
28
views
Why is there a point of orbits along with quantization in case of energy gaps?
As per my textbook and online sources. The definition of Energy bands I have found is this:
A) Energy levels:
( In a simplified view of an electronic structure of a single atom or isolated molecule.
...
- 412
1
vote
3
answers
146
views
Comparing Succesive Ionisation Energies
I am trying to understand successive ionisation energies. In particular, an explanation for why the second ionisation energy is greater than the first ionisation energy. I'm looking for a clear and ...
-1
votes
1
answer
65
views
when would copper material have free electrons [closed]
If you imagine a wire of copper(note that I am not talking about electricity at all). Just only a wire of copper or copper metal or whatever full of copper atoms.
We know that each copper atom has 1 ...
- 119
9
votes
3
answers
1k
views
How does an electrons's wave function change when it moves between energy levels?
I'm taking a class on QM and we're simulating the wave function of an electron in a box at the lowest energy level and I'm supposed to change the simulation to show the wave function for the next ...
-5
votes
1
answer
74
views
What is the energy difference between inner subshells?
For exemple, in silver the energy difference between the 4d 5s subshells is ≈ 4 eV (in the ultraviolet region, that's why it has no color, etc.), but what is the energy difference between some of its ...
-3
votes
1
answer
533
views
What does it mean when we say an atom has infinite energy levels/shells? [closed]
My chemistry teacher told that an atom has infinite energy shells according to Bohr model , where electron reside according to its angular momentum and energy.
But in lower classes/ grades I have ...
-2
votes
1
answer
336
views
How to calculate ionization energy of an atom provided energy of the electron at ground state? [closed]
It is given that in ground state the energy of electron in hydrogen atom is $-2.18\times10^{-18}\mathrm{J}$. I'm required to calculate the Ionization Energy in kJ/mol
Question for reference:
At ...
- 1
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 ...
- 101
5
votes
1
answer
146
views
How can a hydrogen atom ever emit an X-ray photon?
From Scientific American, February 2014:
The Proton Radius Puzzle:
...we had to tune the laser so that it came in with exactly the right amount of energy. The atom would make the jump to the higher ...
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2
votes
1
answer
3k
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
0
answers
103
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Maximum number of Spectral Lines "A better quantum model shows that there will be n^2 transitions"?
I was parsing the following post What is the maximum number of emission lines when the excited electron of a H atom in n = 6 drops to ground state? and came across with the reply from @porphyrin.
cite ...
- 11
5
votes
1
answer
1k
views
Why is it that protons and electrons undergo the same amount of deflection in an electric field if they have the same energy?
The question I have is with respect to this diagram. Which depicts a stream of protons and electrons entering a proton field with equal energy.
Why is it that in the case where the energy of protons ...
user104941
-3
votes
1
answer
71
views
Stability of an atom in absence of EM field
According to Bohr model of atom, electrons move up an energy level in presence of EM field and emit a photon moving down the level.
In complete absence of any external EM field, shouldn't the electron ...
- 63
16
votes
4
answers
5k
views
Why do electrons jump back after absorbing energy and moving to a higher energy level?
Electrons in a shell absorb energy and move to higher energy levels, but they release their energy and jump back to the shell they originally were in. Why do they jump back? Why can they not keep ...
- 189
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
$...
- 412
7
votes
2
answers
4k
views
What are high-energy electrons?
I read that (in cellular respiration) the transported electrons in NADH have a higher energy than those in FADH2.
I can't find a (simple or otherwise) explanation of what a "high-energy" ...
- 267
1
vote
1
answer
251
views
Why does the Heisenberg uncertainty principle work in an atom? [closed]
Where is my logic wrong?
An electron can only assume quantized energies in an atom.
If an electron is localized in space in a hydrogen atom, its radius is known. If its radius is known, its ...
- 21
8
votes
1
answer
337
views
Why is the principal energy of an electron lower for excited electrons in a higher energy state?
Several places state the 'principal energy of an electron' can be calculated as such:
$$E = \frac{2π^2mZ^2e^4}{n^2h^2}$$
Another equation I found was:
$$E = -\frac{E_0}{n^2},$$
where $$E_0 = \pu{...
- 169
2
votes
2
answers
41k
views
What is the maximum number of emission lines when the excited electron of a H atom in n = 6 drops to ground state?
When an electron in a higher energy state jumps to a lower energy state in Bohr’s model of hydrogen atom, it emits a photon which has energy equal to the difference in the energy between the final and ...
- 139
7
votes
1
answer
37k
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Formulas for the number of spectral lines
While reading through Narendra Avasthi's Problems in Physical Chemistry, I came across two formulas on p. 64 (Scanned page):
When electrons de-excite from higher energy level ($n_2$) to lower ...
- 167
2
votes
2
answers
1k
views
How do flame tests give off color if they only emit the colors when the electrons return to ground state?
Since we are constantly holding the element in the fire and the elements only give off the color when the electrons emit the energy that was supplied and return to ground state, why do we only see the ...
- 803
-1
votes
1
answer
38
views
Atoms in Solar Cells
An electric field in solar cells is created through photons knocking electrons off of atoms. What happens to the positively charged atoms once the electrons have been knocked off? Furthermore, are the ...
0
votes
1
answer
236
views
Quantization and Bohr's model
According to quantization it's said that emitted or absorbed energy is quantized.
Then, when it's said in bohr's model an electron changes its orbit (Let's say it goes to a higher energy shell from $...
- 137
1
vote
2
answers
2k
views
Why does a neutral atom of beryllium not have any electrons in a p orbital?
Here's what I understand about quantum number and orbitals, please correct me if anything is wrong:
Electrons enter into these different types of orbitals because they have a higher/lower amount of ...
- 31
3
votes
1
answer
1k
views
Energy levels in non-hydrogen-like atoms
The energy $E_n$ for a hydrogen like atom is given as
$$E_n = -hcR_\ce{H}\frac{Z^2}{n^2}$$
However, aside from on wikipedia where there is
$$E_n = -hcR\frac{Z_\text{eff}^2}{n^2},$$
I can't find ...
- 143
5
votes
2
answers
226
views
What prevents everyday objects from reacting?
This may be a stupid question but I would like to know what prevents chemical reactions from happening among common objects in everyday life? The opposite would be, what requirements must be met for ...
4
votes
0
answers
234
views
Difference between change in energy level and hyperfine energy level?
The second is the duration of 9 192 631 770 periods of the radiation
corresponding to the transition between the two hyperfine levels of the
ground state of the cesium 133 atom.
--> This ...
- 383
0
votes
1
answer
120
views
Excitation of an electron of H-atom from n=2 to any $n_2 $
I got taught that if an electron de-excites from any $n_2 $(where $n_2 >3$) to $n=2$, the energy change can be represented by $$\Delta E=13.6\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)\ \mathrm{...
- 567
2
votes
3
answers
6k
views
Are electron orbitals in a helium atom degenerate?
In a hydrogen atom, the presence of only one electron allows various orbitals' energy states to be dependent only on the principal quantum number and not on angular momentum. Orbital degeneracy and ...
- 123
4
votes
1
answer
2k
views
How are subshells and shells arranged in an atom?
If $\mathrm{2s}$ and $\mathrm{2p}$ are in the second energy level, and $\mathrm{3s}$, $\mathrm{3p}$, and $\mathrm{3d}$ are in the next (3rd) energy level, how are these subshells arranged in space in ...
- 41
3
votes
1
answer
11k
views
What are the effects of the repulsive forces between electron on the potential energy graph for the dihydrogen molecule?
This diagram is from my textbook. It states that as long atoms get closer, the energy decreases due to the attractive forces between the electrons and the nuclei. When the nuclei get too close, the ...
- 1,529
0
votes
1
answer
1k
views
Uniform circular motion of electrons?
Can we use the uniform circular motion formulae to calculate the velocity of an electron along with the formula of radius of nth Bohr orbit? And using that can we calculate the kinetic energy of an ...
- 1,806
2
votes
1
answer
77
views
Electron's Energy In The Atom
I know that the exact (OK most of the times not the exact) energy of an electron can be calculated by solving Schrodinger's differential equation, but can we explain an electron's energy of a specific ...
- 21
1
vote
0
answers
590
views
How much energy is required to make an ion?
So say that I have a normal hydrogen atom (not an isotope, just regular normal hydrogen atom) and I want to make it into an ion $\text{H}^+$. Since to make an ion of that formula I need to take away ...
- 1,441
5
votes
3
answers
11k
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?
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5
votes
2
answers
2k
views
Why is energy released as electrons move?
Why is it that energy is released from electrons when they move from one atom to a more electronegative one?
- 1,529
2
votes
0
answers
363
views
Why does the definition of ionisation energy only include gaseous atoms? [duplicate]
I know that in physics there is thermionic emission and the photoelectric effect. These are both method of removing electrons. I think these affects are only for metals due to their de-localized ...
- 21
2
votes
0
answers
301
views
First ionization energy of hydrogen molecule
If we have the dissociation's energies of hydrogen molecule $\ce{H_{2}}$($D_{0}$) and the corresponding molecule ion $\ce{H_{2}^{+}}$ ($D_{1}$) together with the first energy of ionization of hydrogen ...
- 21
1
vote
1
answer
2k
views
Is the smallest or largest diameter important for the color of a molecule?
I learned that phenol absorbs longer wavelengths than benzene because the electron cloud is bigger.
But what is about Penta-1,2,3,4-tetrien (1) and 2,2,-Dimethylpropane (2)?
(1) has the largest ...
- 113
1
vote
2
answers
234
views
Electron affinity
Concerning the liberation of energy when an atom that is close to the configuration of a noble gas:
Where does the energy dissipated from an atom upon receiving an electron come from?
- 11
1
vote
1
answer
136
views
Where do the electrons not in the S1 orbital get this "extra energy" from?
In this video, Sal Khan says that an electron reaches a higher energy state if the electron possesses more energy. So I assume that, say in the case of carbon, the electrons not in the S1 orbital have ...
3
votes
3
answers
6k
views
In nuclear chemistry, how does a neutron split to form a proton and an electron?
I'm studying radioisotopes at the moment and balancing nuclear reactions isn't making sense in that more matter is coming out of the equation in negative β⁻ decay equations:
$$\ce{_6^{14}C -> _7^{...
- 33
2
votes
1
answer
534
views
X-ray fluorescence: where do expelled electrons go?
I'm studying the XRF method cause I'm about to use a WDXRF spectrometer at college so I'm getting all the information about the physics and chemistry behind it.
I'm just curious about one thing, as ...
- 121
5
votes
2
answers
814
views
Energy of the n-th level for an atom
Going through the Bohr's model and his assumptions, I came across with this formula to find the energy of the n-th level of any atom:
$$E = - \frac{Z k_e e^2}{2r_n} = -\frac{Z^2(k_e e^2)^2m_e}{2\...
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99
votes
7
answers
139k
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Why is the 2s orbital lower in energy than the 2p orbital when the electrons in 2s are usually farther from the nucleus?
My chemistry book explains that even though electrons in the $\mathrm{2p}$ orbital are closer to the nucleus on average, electrons from the $\mathrm{2s}$ orbital spend a very short time very close to ...
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