Questions tagged [ions]

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Why does electrolytic conductance increase with dilution?

We are only talking about strong electrolytes. According to my book, conductance increases slightly due to dilution. Explanation given by my book: On the one hand, in a dilute solution, the number of ...
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Charge in atoms in bond

Let us think of a covalent bond between two atoms $A$ and $B$. Since in covalent bond,sharing of electrons take place, valence eletrons of one atom behave as the electrons of the other atom. So since $...
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Positive charge in electrostatics

We know that all charges are caused by excess or shortage if electrons. Since electrons are negatively charged, it makes sense seeing negative charges in motion which we usually see in electrostatics. ...
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What is unit system in this reduction process?

I have read "The Stopping and Range of Ions in Solids", which is published in 1985 about ion implantation. There is a equation in P.53 : $$ \varepsilon=\frac{32.53M_2E_0}{Z_1Z_2(M_1+M_2)(Z_1^...
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6 votes
5 answers
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If lightning is caused by ionisation of air, why does it only last briefly?

I'm comparing lightning and fire - both are related to ionisation of air but lightning happens so fast in a blink of an eye while fire goes on until it runs out of fuel. My question is: despite being ...
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A question regarding how ion thrusters work

The positively charged ions migrate toward grids that contain thousands of very precisely aligned holes (apertures) at the aft end of the ion thruster. The first grid is the positively charged ...
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1 answer
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How are the electrons able to overcome the significant force of attraction of the ions?

The cause of electrical resistance(in a metal) is electrons colliding with themselves and the positive ions. So if the electrons collide with the positive ions, how are they able to overcome the ...
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1 answer
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How does salt lowers the freezing point of water?

At 0 degree Celsius, water molecules slow down enough to bond with each other and ice starts to form. By adding more salt or sodium chloride the freezing point of water becomes even lower, why is that?...
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2 answers
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What is the difference between band gap and first ionisation energy?

To me both the band gap and first ionisation energy seems to be the same thing as both are the energy required to remove the valence electron from the atom. So I am confused whether they b are the ...
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0 answers
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How does higher concentration leads to higher internal resistance in the cell?

Concise Physics mentions that: Higher the concentration of the electrolyte greater is the internal resistance(in a cell). I think that higher the concentration of the electrolyte higher would be the ...
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5 votes
3 answers
650 views

How come the number of wandering electrons is same as the number of the positive ions?

My book mentions the following: Cause of resistance : When an ion of a metal is formed , its atoms lose electrons from its outer orbit . A metal ( or conductor ) has a large number of wandering ...
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What exactly is a "sideband", when it comes to sideband cooling?

I am learning about the cooling and trapping of ions, and have come across sideband cooling. I can't seem to wrap my head around what a sideband, or more specifically, a sideband transition, is. ...
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How to relate laser pulse characteristics to the degrees of ionization of a target (i.e. how many electrons get removed per atom)?

Say I have a lithium foil as a target for a laser. Li has $3$ protons and $3$ electrons and therefore $3$ degrees of ionization associated with $3$ ionization energies (for removing the first, second ...
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1 answer
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Does salting water make it less diamagnetic?

I read some where that adding salt to water makes it less diamagnetic, but I've checked and water, sodium and chlorine ions are all diamagnetic. If salt water really is less diamagnetic, how is it so?...
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Electrons produced in water by ionizing radiation vs. electrons due to electrostatic charge: are they equally reactive?

It is known that one of the things generated in water or aqueous solutions by the ionizing radiations are free electrons that quickly become "hydrated" or "aqueous electrons" (see ...
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Can you generate negative ions using the photoelectric effect?

If a sheet of metal emits electrons by the photoelectric effect, where do the electrons go? Can they be captured by air molecules to produce negative ions? Can you make a negative ion generator using ...
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1 answer
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How can radiation negatively ionize an atom?

Ionizing radiation, as I've learnt it, ionizes an atom by supplying enough energy to essentially "knock" an electron off the atom — that is, by exciting the electron to a level that is gets ...
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About ions cooling and its thermal energy

I'm trying to understand how entropy and ions correlate. let's say we have a isolated ion in a chamber, this ion is supposed having a thermal entropy defined by some formula i don't know, how would ...
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Failure of Drude like model and temperature dependence of ionic conductivity

Purcel models ionic conductivity[1] $\sigma$ in what seems to be a Drude like model, and gets for an electrolite like NaCl $$\sigma \approx Ne^2\left(\frac{N_+ \tau_+ }{M_+}+\frac{N_- \tau_- }{M_-}\...
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Photons in orbit of moving ion

Recently, I've heard about successful experiment regarding Breit-Wheeler process. (Sample article:) https://www.sciencealert.com/physicists-claim-they-ve-finally-observed-matter-being-made-out-of-...
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Charged ions distribution in a cylindrical container

In a cylindrical container of radius $R$ and height $h\ll R$, with vertical axis, is contained an ionized gas (total sum of the charges $=0$). The particles with positive charge $q>0$ have mass $M$ ...
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Time of flight mass spectrometer high energy regime shortcomings

Consider a time of flight experiment that is used to determine Total ionization cross sections for electron impact in a molecule, for instance as described in this paper: https://aip.scitation.org/...
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Which type of material would I have to study to get a deep understanding of the ionization phenomenon?

I've been collecting basic information about the phenomenon of ionization. I know what it is and its sources and types (as well as the type of particles that can cause it). However, it is my goal to ...
2 votes
0 answers
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What is the strength of Coulomb crystals?

Coulomb crystals are solid crystals made of ions embedded in an electron gas. They constitute much of white dwarfs and the crust of neutron stars. In the case of neutron stars it is known that they ...
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1 vote
4 answers
183 views

Can we shake an atom that hard so the nucleus flies out?

Take a single atom. A collection of hadrons (nucleons) sitting at the center rather inert, surrounded by orbitals of leptons (electrons). Somehow we let the atom move slowly oscillatory. Then we ...
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Ramsauer–Townsend effect and Thermal Runaway in Thyratrons / (vacuum tubes)

A few years ago an EE told me that the Townsend effect was involved in thermal runaway within vacuum tubes. I can't seem to find any specifics on this on the internet. Can anyone disprove / verify and ...
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4 votes
1 answer
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Why is hydrogen ion much more likely to be +1 than -1?

With the chem 101 description of the periodic table, we ascribe certain "desires" to elements. Atoms "want" a full valence shell; for alkali metals, that is most easily done by ...
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1 answer
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Adjustment of spin quantum number in ionic bond

I would like to describe my problem with an example: The spin of 11th electron of Na (Sodium) atom could be $\pm \tfrac 12$. Let's consider in this case it is $+\tfrac 12$. The spin of 17th electron ...
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0 answers
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Are ionic crystals, band insulators?

Ionic crystals are considered as electrical insulators. Is there a proof that they are insulators from the point of view of electronic band theory? In other words, is there a proof that ionic crystals ...
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1 answer
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Generating electrical current using sea or ocean currents

I'm curious to know is this concept can work. Place two metallic plates in a body of salt water. Connect a power supply in order to attract ions close to each plate. Place two coils as illustrated ...
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1 vote
1 answer
67 views

Why does the high charge density of a proton prevent it from existing alone in a solution?

My chemistry lecture notes say that when an acid is in a solution, it can give off protons, but only when there is another molecule that can accept those protons. It is said that the reason why the ...
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1 answer
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Identifying variable in an ion thruster problem

recently came across a school revision problem introduced my teacher about ion thrusters. With the assumption that we are ionising air (Nitrogen) and that the ions accelerate by mutual repulsion ...
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2 votes
2 answers
125 views

In plasma when we introduce a positive test charge then electron cloud shield it, why don't they stick to it and neutralise it?

When a positive test charge is introduced into a plasma, then there is a formation of an electron cloud which shields it. Why don't these electron stick to the positive charge and just neutralise it? ...
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1 answer
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Why Debye shielding occur in plasma?

Why Debye shielding occur in plasma when we introduce a test charge? Does Debye shielding depends on test charge When it is introduced in plasma?
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2 votes
2 answers
1k views

What is quasineutral in plasma physics?

What is quasineutral gas? In plasma physics, what exactly quasineutral means? In definition of plasma, it is written that plasma is a quasineutral gas of charged and neutral particles which exhibit ...
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1 vote
2 answers
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"Crystal electric field," zero temperature, and the idea that the crystal electric field will have a "symmetry reflecting that of the crystal lattice"

I was searching for information on "phonon broadening" in the context of lasers. I found the document Paper BIII: Diatomic Molecules & Laser Physics by Prof. Simon Hooker, where chapter ...
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-1 votes
1 answer
52 views

Electric arc and electric spark differences? [duplicate]

Why does an electric spark occur discontinuously while an electric arc is not extinguished as long as the current is maintained?
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1 vote
1 answer
101 views

Why does lightning strike lightning rods sometimes?

I watched some videos and read a lot of posts mentioned that pointy shaped objects create denser electric field than other objects (especially spherical ones), that's why people use pointy and ...
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1 vote
0 answers
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Does membrane permeability affect the equilibrium reached by two different concentrations of equally charged ions?

I'm asking this question to aid understanding of the formation of membrane potential in a cell from electrochemical gradients of ions e.g. why the membrane potential is skewed towards the equilibrium ...
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0 votes
1 answer
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Charge state in Accelerator physics

while asking for calculation of magnetic rigidity for accelerators, I am seeing notations like '238-U-28+' & '197-Au-77+ Previously I was comfortable seeing charge state like 40-Ca-1+ ions before. ...
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1 vote
1 answer
29 views

Can ions / protons / charge liquids generate magnetic fields

can ions moving in a solution generate magnetic field if yes then why is it not more commonly used. lithium ion's in batteries pass from cathode to anode separated by a membrane to discharge the ...
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0 votes
1 answer
47 views

Charge measurement and mass spectrometer

When reading about how we can use a mass spectrometer in order to determine the mass of atoms/ions, several books that I have considered say that a mass spectrometer allows for a measurement of the ...
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0 votes
1 answer
95 views

Continuity of electric displacement field inside ion solution

I am trying to model transport of ions (calcium, potassium, chloride etc.) in water. The ions move because of the influence of diffusion and electric force and can be modeled by the Poisson-Nernst-...
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1 answer
255 views

What is the difference between ion beam and laser?

What is the difference between laser beams and ion beams, especially in inertial confinement fusion? In inertial fusion, we use lasers as well as ion beams for driving the reaction. What is the ...
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1 vote
3 answers
71 views

Atom charge forces and ionic bounding [duplicate]

Why do electrons form shells/clouds around nucleus? If electron is negative charge and protons in nucleus are positive they should attract each other and as a end result stick in one place? Second ...
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1 vote
1 answer
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Difference between ions, free electrons, and excess charge

This part from University Physics turned my world upside down. What is the difference between ions, free electrons, and excess charge? Also, ions and free electrons make up a neutral conductor? Bloody ...
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1 answer
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Does potassium ions have a longer range attraction than sodium ions or hydrogen ions?

Electronegativity decreases with period in in the periodic table. The explanation for that is because the distance to the nucleus decreases with each orbital shell of electrons, if I got that right. ...
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1 vote
0 answers
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An electron leaves a neutral droplet. After that, a singly-charged positive ion joins the droplet. What is the resulting charge of the droplet? [closed]

I know an electron's charge is $~1.6 × 10^{-19} C$, which would mean that after leaving it would leave the droplets charge as $+1.6 × 10^{-19} C$ (right?) but I do not understand the effect of the ion ...
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1 vote
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Plasma behavior around the Electric spark in air

When a pointed cathode and a plane anode are subjected high voltage dc and there is air between them, and spark is formed and the spark is allowed to sustain for few micro seconds, how the electrons ...
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1 vote
0 answers
19 views

Are ions in a flowing solution affected by magnetic fields

Are ions which has been dissolved in water affected by magnetic fields in any measurable way? Basically, I want to measure different ions in a water solution. Would it be possible to build a mass ...
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