What is Energy level: Definition and 140 Discussions
A quantum mechanical system or particle that is bound—that is, confined spatially—can only take on certain discrete values of energy, called energy levels. This contrasts with classical particles, which can have any amount of energy. The term is commonly used for the energy levels of the electrons in atoms, ions, or molecules, which are bound by the electric field of the nucleus, but can also refer to energy levels of nuclei or vibrational or rotational energy levels in molecules. The energy spectrum of a system with such discrete energy levels is said to be quantized.
In chemistry and atomic physics, an electron shell, or principal energy level, may be thought of as the orbit of one or more electrons around an atom's nucleus. The closest shell to the nucleus is called the "1 shell" (also called "K shell"), followed by the "2 shell" (or "L shell"), then the "3 shell" (or "M shell"), and so on farther and farther from the nucleus. The shells correspond with the principal quantum numbers (n = 1, 2, 3, 4 ...) or are labeled alphabetically with letters used in the X-ray notation (K, L, M, N…).
Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons. Since electrons are electrically attracted to the nucleus, an atom's electrons will generally occupy outer shells only if the more inner shells have already been completely filled by other electrons. However, this is not a strict requirement: atoms may have two or even three incomplete outer shells. (See Madelung rule for more details.) For an explanation of why electrons exist in these shells see electron configuration.If the potential energy is set to zero at infinite distance from the atomic nucleus or molecule, the usual convention, then bound electron states have negative potential energy.
If an atom, ion, or molecule is at the lowest possible energy level, it and its electrons are said to be in the ground state. If it is at a higher energy level, it is said to be excited, or any electrons that have higher energy than the ground state are excited. If more than one quantum mechanical state is at the same energy, the energy levels are "degenerate". They are then called degenerate energy levels.
I am a high school student.. I have come across so many times that lower energy state of matter is more stable than higher energy states .. I can't understand why. Someone help me out.. Thanks.
Question
Particle in a box (2D)
Determine the energy levels (degeneracy) of the lowest three
I found that E = A (4a^2 + b^2)
where A is a constant
a and b are positive integers (principle quantum number)
My steps
I assume 4a^2 + b^2 = k
where k is also a positive integer...
Homework Statement
Suppose we have reason to suspect that a certain quantum object has only three quantum states. When we excited such an object we observe that is emits electromagnetic radiation of three different energies: 2.48 eV (green), 1.91 eV (orange), and 0.57 eV (infrared). Propose...
When an atom absorbs a photon of light and gets into an excited state, can it ever make a single jump back down to the ground state? For example, if an atom absorbed a blue photon of light then jumped straight back down to the ground state would it then emit a blue photon? How does emission...
What if an electron at a certain energy level receive a little bit more energy from a photon than the difference between its current energy level and the next one, will it jump to it ?
I see written in textbooks that the photon energy must exactly match the difference between two energy level...
Say for a simple hydrogen atom, an electron absorbs just the right amount of energy such that it jumps up from energy levels n = 1 to n = 5. When it comes back down, is it possible to say, do n = 5 to n =3 to n = 2 to n =1, releasing 3 photons with their respective specific frequencies/energies...
1. Consider doubly ionized Lithium (Li++), which has one electron orbiting a +3 charge nucleus. Assuming the electron is in the ground state (n=1), what is the maximum wavelength of light, λ, that would completely ionize the Li++? (free the electron from the nucleus),
all variables and...
Hi,
can anyone help me explain more detail about energy level split with the system of two atoms?
Please see this video at 06:32:http://www.youtube.com/watch?v=y_GZn4o8gaE
Thank you.
This question is off my forum , and I was just wondering if anybody could help.
I don't understand why -1/2 is the higher energy level and +1/2 is the lower energy level.
For spin state -1/2, if the external magentic field B0 and magnetic moment uZ oppose each other, surely the energy...
Hello,everyone! I want to know if there is database which can tell me the energy level diagram of atom. I have consulted NIST Atomic database,but I can't find energy level diagram. so anybody can help me ? I WANT to get the energy leverl diagram like hydrogen atom in modern books(potential...
In n-type semiconductor, Can electron stay between donor energy level and valence band?
Can I say that the donor energy level here refer to the Fermi level?
Thank you
Given a simple atom like the Bohr atom (and possibly generalized to any other atom), I know that an electron can transition from one energy level to another, either by absorbing or releasing a photon of a precise hf. How much time does an electron take to make a transition from one energy level...
Homework Statement
http://i.imgur.com/j8JdV.png
Homework Equations
http://i.imgur.com/Wobmo.png
The Attempt at a Solution
I wasn't really sure where to start with. Can energy level be calculated at any of these, since the signal stretches to infinity?
I'm very thankful for any...
Say a photon was absorbed by an electron at 1s in an oxygen atom but it only had enough energy to move it to another energy level that was already occupied such a 2s etc. What happens to this photon?
What is the energy of the n = 1 energy level in the
B4+ hydrogen-like ion?
I need it to 4 significant figures...
I know the equation is
En=Z squared X -13.60 /n squared... however I can't work out the answer to four significant figs
Would like to see if I've understood this question somewhat. :-)
Homework Statement
A doubly ionised Lithium atom (Li^++) has two of its normal complement of electrons removed. The energy levels of the remaining single electron ion are closely related to those of the neutral Hydrogen...
Hi, I have some very basic questions regarding electron energy levels/states.
In the basic atom model when an electron becomes excited (i.e. absorbs a photon or collides with a nearby atom or particle) and moves into an energy state greater than its ground state, must it always eventually...
Why can't an electron have a even lower energy level in atom and be closer to the nuclei? (as the next step is to fuse with one of the protons and make neutron.. )
Hello Forum,
I am looking at the energy levels between the n and p regions of a diode. The p-side has a conduction band that starts at a higher energy (same for the valence band).
The n-side has the valence and condution bands that are at lower energy.
The Fermi energy line is the same...
From what I understand, degenerate matter is highly compressed matter with high energy, but how can you increase its energy if there is no more room for particles to exist in for a higher energy state?
Also I noticed this is not in the section I thought I put it in.
in the book of quantum mechanics concept and application by Zettili, chapter 4 write a theorem, that is:
in one dimensional problem the energy level of a bound state system are discrete and not degenerate.
i can not prove this theorem.
can you help me to do this!
Homework Statement
Consider a photon that is barely capable of causing a photoelectric effect when it strikes a sodium plate having a work function of 2.55eV.Homework Equations
Find the minimum energy level n for a hydrogen atom that can be ionized by such a photon, and the speed of the...
A particle in 1 dimension moves under the influence of a potential V(x)= a(x)^6 where a is constant. For larger n ,the quantized energy level depends on n as
E = (n)^3
E = (n)^4/3
E = (n)^6/5
E = (n)^3/2
Homework Statement
Calculate Efi with respect to the center of the bandgap in silicon for t= 200, 400, 600 kelvin.
Homework Equations
ni = Nc e^-((Ec- Ef)/(kt))
k = boltzman constant
t= temperature in kelvin
Ec = energy level of the conduction band
ef= fermi energy level
ni=...
Energy level of hydrogen atom -- with the electron replaced by a positron
The energy level of a hydrogen atom is given by (without fine structure consideration)
Eh = -13.6 eV / n^2
Suppose -- if the electron is replaced by a positron, what would happen to this energy level?
The resulting...
Hi,
This is probably a really simple question, I am just trying to get my head around why electron-electron-interactions raise the energy level. If electrons repulse each other, why does this cause the energy levels to increase?
Thanks
currently I'm studying the topic entropy. According to my text, entropy will increase when the accessible energy levels (microstates) increase. One of the approach to achieve this, we can decrease the spacing between energy levels by increasing the volume of the system.
i'm confused with...
My textbook says that, the energy level of an electron is decided by the pattern of charges surrounding it.
Can anybody explain how. Simple language please, I'm in 12th grade. Kindly provide example, if possible. Thank you.
In MR there is the resonance condition that for a proton in a lower energy state, a photon with a frequency that matches the energy separation between states, E=hf, can transmission the proton to the higher energy state by absorbing said photon.
The question then is how long does this...
Si is doped with 6 x 1015 cm-3 donors and 2 x 1015 cm-3 acceptors. Find the position of the Fermi level with respect to Ei at 300 K.
i know the equations are
(for n-type) EF = kT ln(ND/ni) + Ei
(for p-type) EF = kT ln(ni/NA) + Ei
however, since the problem gives me both donors and...
The question occurred to me when I was thinking about black radiation. It is critically depend on the fact that the photon number is variable. Therefore I wonder why energy level transitions of atoms can only emit out the massless photons, but not any other kind of particles, even some with...
Homework Statement
A certain laser outputs pure green light (photon energy 2.5 eV) with power 500 milliwatts (0.5 watts). How many photons per second does this laser emit?
Homework Equations
not exactly sure, I know that Watts are equal to Jouls/sec
and that the electronic energy of a...
Hi, I'm having problem about Atomic energy levels.
Who can help me find Images about Atomic energy levels diagrams of chemical elements.
Thanks^^.
Example: Atomic energy level diagram of Hg:
[PLAIN]http://ca8.upanh.com/15.290.19566358.Z7p0/fig1.gif
You can contact me.
I'm Hoang An
Homework Statement
A hydrogen atom is in a state with energy -0.278 eV.
Homework Equations
L = nh'
The Attempt at a Solution
The answer book says to do E_n = (-13.6 eV)/n^2 but I can't find this equation in our book. Is the 13.6 a significant number or just a different number...
Hi All,
I'm pondering some questions around photon absorption causing bound electrons to move to higher energy levels.
When a photon strikes an atom, what will happen if the photon has more than enough energy to make an electron move to the first excited state, but not enough for it to...
The problem is number 5.10 in Griffths introduction to quantum mechanics, It goes as follows:
Discuss (qualitatively) the energy level scheme for helium if (a) electrons were identical bosons, and (b) if electrons were distinguishable particles (but with same mass and charge). Pretend these...
Homework Statement
a) Consider a sample of hydrogen atoms at a temperature of 300 K.
i) What is the ratio of the number of atoms in the n = 2 energy level to those in the n = 1 level?
ii) At what temperature would the ratio be 1/10?
b) Assume that the conduction electrons in...
This thread is related to another question that I have been pondering.
In most objects that we experience on a daily basis (a green shirt for example), we know that most of the frequencies of light striking the object are absorbed.
I simply can't believe that the atoms in the shirt have...
Can anyone help with interpretation of this energy level diagram for Lithium-6 I found on internet--it is from the Duke University department of Physics.
http://www.tunl.duke.edu/nucldata/figures/06figs/06_03_2002.pdf
I am not sure I understand the equation for the 13.3 MeV energy level...
Homework Statement
Considering only orbital angular momentum, estimate the energy level separation between electron states in a magnetic field of 1 Tesla applied along the z direction.
Homework Equations
I am confused by how to even start this question! Isn't orbital angular momentum...
an atom has 3 non-degenerate E levels, = 0, e, 2e
What is the prob of occupancy of each energy level as T-> zero and infinty and why?
for E=0
I imagine that the prob for T->0, is 1 is one or approaching one as as the temp approaches absolute zero electrons occupy the lowest state
as...
Textbook: "Chemistry" by Silberberg. 5th Edition. Page 306
"Electrostatic effects play a major role in determining the energy states of many-electron atoms."
Can someone help me understand this statement? "Electrostatic effects" is not in the textbook glossary, and I'm not having luck...
I am doing an Atomic & Molecular physics course in Germany as part of my year abroad. A notation that is used in this course to denote energy levels is in the form below. I cannot find a good explanation of how it works, (and this may sound stupid) but i cannot find a mention of it in the notes...
How do you know how many valence energy level you have by just looking at the periodic table?
because you know that the group number tells the valence electrons right. :)
so what about valence energy level? :D