All Questions
49
questions
99
votes
7
answers
139k
views
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 ...
- 1,827
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
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 ...
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 $$E_0 = \pu{...
- 169
7
votes
2
answers
4k
views
What are high-energy electrons?
I read that (in cellular respiration) the transported electrons in NADH have a higher energy than those in FADH2.
I can't find a (simple or otherwise) explanation of what a "high-energy" ...
- 267
7
votes
1
answer
37k
views
Formulas for the number of spectral lines
While reading through Narendra Avasthi's Problems in Physical Chemistry, I came across two formulas on p. 64 (Scanned page):
When electrons de-excite from higher energy level ($n_2$) to lower ...
- 167
5
votes
1
answer
1k
views
Why is it that protons and electrons undergo the same amount of deflection in an electric field if they have the same energy?
The question I have is with respect to this diagram. Which depicts a stream of protons and electrons entering a proton field with equal energy.
Why is it that in the case where the energy of protons ...
user104941
5
votes
3
answers
11k
views
Energy of photons emitted by de-excitation of electrons
When an electron of an atom returns from an excited state to the ground state, it emits energy in the form of a photon. How does the change in energy level compare to the energy of the emitted photon?
- 51
5
votes
2
answers
226
views
What prevents everyday objects from reacting?
This may be a stupid question but I would like to know what prevents chemical reactions from happening among common objects in everyday life? The opposite would be, what requirements must be met for ...
5
votes
2
answers
814
views
Energy of the n-th level for an atom
Going through the Bohr's model and his assumptions, I came across with this formula to find the energy of the n-th level of any atom:
$$E = - \frac{Z k_e e^2}{2r_n} = -\frac{Z^2(k_e e^2)^2m_e}{2\...
- 325
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 ...
- 1,795
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
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
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
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