The electron is a subatomic particle, symbol e− or β−, whose electric charge is negative one elementary charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron has a mass that is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum (spin) of a half-integer value, expressed in units of the reduced Planck constant, ħ. Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: they can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavelength for a given energy.
Electrons play an essential role in numerous physical phenomena, such as electricity, magnetism, chemistry and thermal conductivity, and they also participate in gravitational, electromagnetic and weak interactions. Since an electron has charge, it has a surrounding electric field, and if that electron is moving relative to an observer, said observer will observe it to generate a magnetic field. Electromagnetic fields produced from other sources will affect the motion of an electron according to the Lorentz force law. Electrons radiate or absorb energy in the form of photons when they are accelerated. Laboratory instruments are capable of trapping individual electrons as well as electron plasma by the use of electromagnetic fields. Special telescopes can detect electron plasma in outer space. Electrons are involved in many applications such as tribology or frictional charging, electrolysis, electrochemistry, battery technologies, electronics, welding, cathode ray tubes, photoelectricity, photovoltaic solar panels, electron microscopes, radiation therapy, lasers, gaseous ionization detectors and particle accelerators.
Interactions involving electrons with other subatomic particles are of interest in fields such as chemistry and nuclear physics. The Coulomb force interaction between the positive protons within atomic nuclei and the negative electrons without, allows the composition of the two known as atoms. Ionization or differences in the proportions of negative electrons versus positive nuclei changes the binding energy of an atomic system. The exchange or sharing of the electrons between two or more atoms is the main cause of chemical bonding. In 1838, British natural philosopher Richard Laming first hypothesized the concept of an indivisible quantity of electric charge to explain the chemical properties of atoms. Irish physicist George Johnstone Stoney named this charge 'electron' in 1891, and J. J. Thomson and his team of British physicists identified it as a particle in 1897 during the cathode ray tube experiment. Electrons can also participate in nuclear reactions, such as nucleosynthesis in stars, where they are known as beta particles. Electrons can be created through beta decay of radioactive isotopes and in high-energy collisions, for instance when cosmic rays enter the atmosphere. The antiparticle of the electron is called the positron; it is identical to the electron except that it carries electrical charge of the opposite sign. When an electron collides with a positron, both particles can be annihilated, producing gamma ray photons.
According to QM, given two entangled electrons A and B, if you measure the y-axis spin on A to be up, then you know electron B's y-axis spin is down.
Also according to QM, if i understood it properly, you cannot then go on to measure the x-axis spin on B, because then you would know both y...
σx|x>=+|x>
σx|-x>=-|-x>
These equations also follows for σy and σz corresponds states |y> and |z>.
if we measure along axis X then X state vector let it go which means up spin and opposite not go through which means down spin.
and also same for y and z axis.
But,
σx|u>=|d> σx|d>=|u>...
Copper has one valence electron, but it can lose more than one when forming cupric compounds. I had thought it could only lose the valence electron. How can this happen?
If this is true, how does an electron from the d orbital jump to a higher orbital if only valence electrons can make the jump?
We know that can't measure both position and momentum simultaneously whether both are orthogonal.
If i measure position one entangled electron and momentum on other electron for single state then how Heisenberg's uncertainity princple works?? so We may know the both parameter.
In the case of an atom of Cesium ejecting an electron, it would lose one electron from the 6s orbital. The 6s orbital is very high in energy and similarly so would the electron that is ejected from it, right?
So if there was a Nitrogen atom as well, how would it be possible that the Nitrogen...
Hi,
suppose we have a proton at point A and an electron at point B, at a distance of 1cm , separated by a screen.
If we remove the screen one would expect the particles to meet and clash somewhere near point A, but I read this never happens.
Can you explain why it's so and what exactly happen...
Dumb question, but something I don't get.
I see this expressed in many basic examples of what voltage is. You have 1 object that has too many electrons and 1 object has too little. The potential difference between them is what is expressed as/in volts. If you connect a conductive wire...
Which bulb is really more collisions of electrons inparallel connection?
Maybe we can easily get the conclusion about this question.
The intensity of bulb's light is depend on the power of electricity(IV), so the upper blub has more number of collisons between electrons and atoms.
but I...
Recently a few friends and I were discussing the Fermi sea.
One friend made the statement that if you could access the electrons from the Fermi Sea you could use the material you accessed them from as an electron source. Didn't make sense to me but it got me wondering.
My question is, What...
Do electrons only "feel" the electric field?
Imagine that you're an electron.
You are always at rest in your inertial frame so that you do not "feel" the \mathbf{v} \times \mathbf{B} term of the Lorentz force.
Thus, from your perspective, you only ever "feel" an electric field...
I know that positively charged cation move toward cathode which is the negative terminal and the negatively charged anion move towards anode which is positive terminal
Why does in galvanic cell cations are moving toward cathode which is positively terminal?
And why in galvanic cell...
Homework Statement
P-type silicon can be doped in the range from 5x1014 cm-3 to 1020 cm-3. Determine the maximum possible number of minority electrons in a neutral P-type region if the device area is limited to AD = 1 cm x 1 cm and the thickness of the P-type region is limited to tP=100 μm...
I am not sure if this is the right place to post this, so please let me know...?
If electrons pop in and out of existence, how does that relate to the law of the conservation of matter? The electrons can't just disappear. Are the electrons just visiting the other element in the molecule? Like...
If the electrons closer to the nucleus experience greater electrostatic attraction from the nucleus, would not the closer electrons require more energy to stay in orbit? Also, the electron shielding from the inner electrons would reduce the energy required to stay farther away from the nucleus...
Could anyone please explain the mechanism of diffraction of electrons through the single hole. Have a look on the picture attached.
It says if we would shoot only one electron at a time, the pattern would be the same.
Things which are confusing me:
1. If the source of emitted electrons is far...
Why is the probability of finding an electron of s orbital in the nucleus highest? Is Quantum Tunneling involved? If so, won't the electron need a large amount of energy to pass through the nucleus?
Homework Statement
A negatively charge balloon has 2.4 μC of charge. How many excess electrons are on this balloon? The elemental charge is 1.6e-19 C. Answer in units of electrons.
The attempt at a solution
I keep getting 1.5e13 electrons but the system is telling me it's wrong. I put it in...
In the paint document you will see on the LHS a picture of a circuit diagram then on the RHS you will see a pictorial representation of an electron in the circuit located at an arbitrary point
My question (which is in the paint document): I want to know why the electrons flow in the direction...
i have a made a thread a few hours ago with something related to this
but i would like to know
do electrons push each other in a circuit ?
that would explain the constant intensity across a circuit before electrons even reach a resistor .
i mean they push each other like some kind of...
Homework Statement
A 48.7 g ball of copper has a net charge of 2.2 µC. What fraction of the copper's electrons have been removed? (Each copper atom has 29 protons, and copper has an atomic mass of 63.5.).
Homework Equations
The Attempt at a Solution
Number of electrons normally present ...
Which mechanism in semiconductors is responsible for electron excitation from valence to conduction band in thermal equilibrium at temperature T? Do valence electrons take their excitation energy from the lattice by absorbing phonon? If so, they can be excited at each arbitrary temperature no...
Homework Statement
A cubical box whose sides are length L contains eight electrons. As a multiple of $$\frac{h^2}{2mL^2}$$ what is the energy of the ground state of the eight electrons?
Assume the electrons do not interact with each other but do not neglect spin.
Homework Equations...
Are electrons in the, say lowest energy level, shell, of an atom, always entangled?
i.e. Do electrons (in a shell) have to be necessarily entangled?
Is there any maths (law of conservation of spin/momentum etc) that says so?
Any relation with Pauli's exclusion principle?
Hello,
I need to understand the following:
Considering an element Sulfur - S which has 16 electrons.
How do we calculate the valency electron of S?
Please correct me if I am wrong:2+2+6+2+4=16. So, the valency electron = 4+2=6
Is it that always valency electron is the addition of...
how can the number of electrons, n, in a reaction equation be found generally? for example:
Tl3+ + 4I– → TlI4–
I2(s) + I–(aq) → I3–(aq)
Tl+ + I3- → Tl3+ + 3I-
How to work out standard electrode potential from K or vice versa depends on value of n. for these 3 I know they are n=1, n=2 and...
We are taught that a reason for the stability of half filled or fully filled orbitals is due to the high exchange energy.
Now i get why the exchange energy would be higher compared to other configurations but i don't understand why electrons present in degenerate orbitals would want to exchange...
An electron doesn't move in an orbit round the nucleus. It is in a diffused state.
Please explain what is the meaning of this statement and what is diffused state.
I've been puzzling over things I've read about quantum physics as it relates to reports of things "seen" and the nature of the concepts/semantics/assumptions involved. If this sounds vague its because my thoughts are not fully formed on this. Some detail:
In a new article titled: "Physicists...
I know that if we shoot narrow beam of electrons at the crystal (we don't change the angle) we will get a diffraction of electrons according to the brag's law. Therefore we get minimums and maximums on the screen around the crystal.
Until now we have been dealing with problems where...
Okay, so when a photon travels near an electron orbiting some atom, the electron then absorbs the photon (given that it has enough energy) and causes the electron to jump up an energy level. My question is what happens when a photon has a little more than enough energy to bump up the electron...
I realize this is something I should probably know intuitively, but why are core states (generally) treated relativistically in density functional calculations? What exactly makes these relativistic bound states rather than non-relativistic? I think this is some basic physics I'm forgetting.
I would love some clarification on a gamma ray process. This is what I understand so far:
Electrons are accelerated at 19MeV at a cathode which is releasing gamma ray photons with an energy of 1.9MeV. Is it possible to generalize the emission number of photons (roughly) to be equal to the...
Forgive me in advance if this appears to be a dumb question but, as I was reviewing a few basic chemistry topics, namely orbital hybridization, I came across a question. From what I gather, according to Hund's Rule, an electron must be put into all open orbitals before the remaining orbitals can...
1. Homework Statement
ClO2+ ion:
A. How many total valance electrons does this ion have?
B. Which atom is the central atom?
C. How many bonding electrons are there between the central atom and each of the other atoms?
D. How many nonbonding electrons are there on the central atom?
2...
Homework Statement
Use a piece of scratch paper to draw the Lewis structure for the ClO2+ ion, and then answer these questions (be sure to answer all of them):
A. How many total valance electrons does this ion have?
B. Which atom is the central atom?
C. How many bonding electrons are...
I know that electrons flow across the wire from the source to the receiver, but would it be possible to keep these electrons on the wire after disconnecting the source and receiver?
I've had this strange theory for a long time.
If a free floating proton has a tiny amount of mass, wouldn't excelating it to near C increase its mass or energy nearly infinitely?
If this is so, if we run a wire and fire electrons down its length let's say 100 times per second.
Then fire...
So i was wondering if perhaps a atoms electrons protons and neutrons determine all of its characteristics, such as the hydrogen atom. having only one electron and one proton. it makes it turn into a liquid and solid very close together, and a gas anything above about -259.1°C. and the...
Hello everybody, I am a first year and I have one more question.
To what degree do electron contribute to nuclear decay?
(Do electron which can 'spend' some time in the nucleus cause bigger decay?)
Thanks in advance :)
Homework Statement
Homework Equations
The Attempt at a Solution
Let magnetic field be inside the plane of sheet (towards -ve z-axis)
At any instant of time, let the components of velocity of electron be ##v_x## and ##v_y##.
Then ##F_x=ev_yB_o## (i) and ##F_y=-ev_xB_o## (ii)...
I took this picture from forum aboutcircuits to illustrate current flow in NPN transistor.
Here is what I am confused:
A few at Figure above(a) fall into holes in the base that contributes to base current flow to the (+) battery terminal.
Why these electrons that fall into holes necessary...
Hello all,
I am in need of understanding of magnetic fields. More specifically i was wondering exactly why there is a magnetic field around a wire with current moving through it. Where i am going with this is.. if i had plasma contained, and i managed to get it moving in the container, would...
It is the procedure you do to get ground term symbol in LS coupling. What is meant by this "ground term"? As in a physical meaning.
If you don't know the procedure it is in this link: http://en.m.wikipedia.org/wiki/Term_symbol, please seek "Ground State Term Symbol" Section.
Question. Is there a quantum reason why a lone electron in any of the three available (x,y,z) 2P orbital energy states must always be spin-up or spin-down ?
Every figure I see always shows a single electron as spin-up for the three 2P energy states, but is there a quantum theory constraint...
In some texts about plasmas, the plasma oscillations are discussed at the extreme of no Thermal motion. One example is the one in wikipedia:
But I can't accept that approximation.Because it is assuming that we have a kind of motion called thermal motion and other kinds which arise from other...
I wish to better understand the configuration situation for the outer most valence electrons for the d-block elements, Sc to Zn.
I am having a problem understanding how to predict where the two outer most valence electrons must be located for some of the ten d-block elements? For some...
Hello,
Wave functions and energy levels... What particles are being described by Schrodinger's equation? If we are talking about energy levels, do we mean the energy levels in an atom? Other particles, such as electrons or quarks... do they have energy levels, or are they too small for us to...
Let's say you have 2 batteries, both 1.5 V. If you put your red voltmeter lead on the + of one battery and your black voltmeter lead on the - of the other battery, and assuming the two batteries are not touching, the voltage you read is zero. I know this is a simple question, but why? Why don't...
Was reading about runaway electrons in magnetic fusion. Had me thinking what would be the benefit/cost of engineering a device which creates a beam of reletivistic electrons. What would be the best way to extract energy from this system and does it even matter the speed they are traveling?