What is Ions: Definition and 343 Discussions

An ion () is a particle, atom or molecule with a net electrical charge.
The charge of the electron is considered negative by convention. The negative charge of an ion is equal and opposite to charged proton(s) considered positive by convention. The net charge of an ion is non-zero due to its total number of electrons being unequal to its total number of protons.
A cation is a positively charged ion with fewer electrons than protons while an anion is negatively charged with more electrons than protons. Because of their opposite electric charges, cations and anions attract each other and readily form ionic compounds.
Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron and a positive ion. Ions are also created by chemical interactions, such as the dissolution of a salt in liquids, or by other means, such as passing a direct current through a conducting solution, dissolving an anode via ionization.

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  1. Cocoleia

    I Rectangular wave, extraction of ions from a stopping cell

    Hello. I'm not sure if this question is to project-specific, but I will try to explain as best that I can. I am working with a system such as this one, with only a few differences: http://www.sciencedirect.com/science/article/pii/S0168583X1400706X it is a cryogenic stopping cell. The part I am...
  2. neilparker62

    B Equation for Conductivity of Aqueous Solutions

    I have found a lot of data and graphs showing conductivity (micro-mhos) vs % by weight of various salt solutions. The salts for which graphs appear particularly linear are those of alkali Earth metals - eg sodium, potassium - KI, KBr, KCl etc. Is there a theoretical equation for conductivity vs...
  3. H

    A Question about energy transfer between Rare-Earth ions

    Dear all, I have a question about one of the values presented in a paper, which is crucial in calculating energy transfer probability between two Yb3+ ions. This is the paper: T. Kushida, "Energy Transfer and Cooperative Optical Transitions in Rare-Earth Doped Inorganic Materials. I...
  4. Amy

    Flux of high charge positive ions, how?

    I need a flux of highly positive ions, at least penta-valent ions (5+ or more, 6+, 7+, ...); there are ion sources that can generate a proton flux, but I need 5+ ions; do you know how I can do that?
  5. Ken H

    Energy imparted to an ion by a magnetic field

    Basically my question is: if an anion is placed by the negative poll of a magnet will it push on the particle?
  6. Biker

    Negative ions affecting galvanic cell voltage

    I saw this more related to physics than chemistry. So I have been trying to model how the voltage is generated in galvanic. I couldn't find any online and I thought it would be a good exercise. I modeled ions as electric charges with different magnitude of charge. Each producing a different...
  7. moenste

    V required so ions passing through the region don't devitate

    Homework Statement Hydrogen ions moving at various speeds are directed at a region of combined electric and magnetic fields as shown in the diagram below. The electric field is between two parallel plates 10 mm apart with a potential difference V across them, while the magnetic field of flux...
  8. A

    How do ions and electrons follow directions in a stellarator

    Hello, I'm a high school student interested in fusion. I've done a bit research online but I got a bit confused how does stellarator like W7-X drives electrons to run in the same direction without plasma current. I know in a tokamak, the plasma current makes electrons follow a certain direction...
  9. G

    How Do You Determine If Compounds Contain Ions and Their Charges?

    Hey, So I've got a homework question which is gradually transforming by brain into mashed potato! Here it is.. Identify which of the following compounds contains ions and state the formal charges on the ions: NaCl, N2, MgO, AlCl3, and CO2. Now, I'm not asking for someone to come in and give...
  10. T

    Chromium (III) ions and NaOH

    Homework Statement Homework EquationsThe Attempt at a Solution I chose A as after googling, I learned it was green. My question is: what is the green-blue precipitate. I am inclined to say [Cr(H2O)6]2+ as it's solution is blue, but ions don't precipitate. I tried searching and could find...
  11. T

    Lowest concentration of ethanoate ions

    Homework Statement A small quantity of each of the following is added to separate samples of an aqueous solution of ethanoic (acetic) acid. Which would leave the lowest concentration of ethanoate (acetate) ions? sodium hydrogen carbonate solutiondilute hydrochloric acidmagnesiumdilute sodium...
  12. iTryToLearn

    Give the chemical formulas for four possible salts

    Lets say you were given an unknown which contains two salts, and your results give you evidence that potassium phosphate, ammonium, and carbonate ions are all present. What are four possible salts that could be your unknown?
  13. R

    Kinetic Salt Effect - Size of Ions

    Hello, Throwing out a question to see if anyone has some insight. The kinetic salt effect describes the variation of the rate constant of a reaction with respect to the ionic strength of the solution. The mathematical relationship considers the ionic strength (molality/ion charges) of the...
  14. D

    Calculating H3O ions in a drop of water at 25 °C

    Hello! Here is a problem that looked easy for me, but my answer differs from the textbook's one. Please, help me to see my mistake. How many H3O ions are present in one drop (0.050 mL) of pure water at 25 °C? Here is how I solved it: There are 1.0 x 10^-7 in one liter. We have 0.000050...
  15. N

    I Determining Ion Speed in a Farnsworth Fusion Ion Collider

    I'm looking to figure out how fast ions are traveling in the fusor I have access to. The chamber is roughly 12-14" long, with a central electrode charged to 75 kV and 5 mA. Is the type of ion relevant? What would I have to do to figure out how fast the ions are moving?
  16. G

    B Electrons and ions -- how long can they exist apart?

    Can ions exist by itself, if it does, does it last for short period of time before it reacts with something else.
  17. L

    Density of chromium ions in ruby

    Homework Statement estimate the density of chromium ions in ruby, assuming that the concentration of chromium in ruby is about 0.05% by weight. Homework Equations decay rate = 0.5x10^3 s^-1 answer: density N (sub T)= 1.6x10^19 cm^-3 The Attempt at a Solution density = mass/volume density of...
  18. B3NR4Y

    Spectator Ions and Molarity Questions

    Homework Statement An aqueous solution of silver nitrate, AgNO3, reacts with an aqueous solution ammonium carbonate, (NH4)2CO3. What are the spectator ions for the reaction? AgNO3 (aq) + (NH4)2CO3 -> A 17.5 mL sample of hydrochloric acid HCl solution required 29.6 mL of 0.250M Ba(OH)2 for...
  19. sciencejournalist00

    Can calcium ions be used as a source of entangled photons

    By heating calcium in a tantalum oven and subjecting the calcium vapor stream to blue laser, calcium atoms absorb the blue photons and emit two photons of lower energy as they decay twice. Once they decay from the highest excited state to an intermediate excited state, and then from the...
  20. S

    Ions & Lorentz Force: Collisions w/ Oppositely Charged Electrodes

    When ions collide with oppositely charged electrodes, do they experience a Lorentz force as they gain or lose electrons? Is there a force, ignoring the repulsion of the positive electrode, in the direction of the blue arrow depicted here? Only information I find is on ionic fluids.
  21. S

    Compress ions in velocity space with magnetic field?

    I was just wondering if a beam of whatever charged particles can be compressed in velocity space if you send the beam through a (strong) magnetic field that is parallel to the beam? The charged particles (that are not moving exactly along the field lines) should spiral in the field in my opinion...
  22. G

    Understanding the Effects of Laser Interaction with Ions in Doped Fibers

    Will a laser exposed to ions (doped fibre) spread out in the direction of polarisation as momentum sends the peaks in one direction and the troughs in another. Or, as total momentum is 0 does the wave continue on straight.
  23. A

    Calculate the concentration (in M) of Cl- ions in solution C

    Homework Statement [/B] PROBLEM #1 You have 3.00 L of a 3.39 M solution of NaCl(aq) called solution A. You also have 2.00 L of a 2.00 Msolution of AgNO3(aq) called solution B. You mix these solutions together, making solution C. Calculate the concentration (in M) of Cl- ions in solution...
  24. W

    How to Create a Charge Separation to Migrate Ions in Solution

    Howdy, I am working in a research lab at The Ohio State University. I need to separate positively charged ions that are intramolecularly bound to negative counterions. I was hoping to use use static electricity to do this. Any suggestions on the power supply/control to do this?Lucas
  25. Hexnovae

    My copper electrodes are discoloring, and I'm not sure why

    For a high school school project I'm trying to build a device that will separate ions dissolved in water. I'm pumping water trough a box that has copper plates in it, and I'm putting that in a magnetic field. Because of Lorentz force the ions should bend off to different sides and heap up...
  26. S

    Difference between the movement of oxygen ions and vacancies

    Hi, I am confused about the difference (if there is any?) between the movement of oxygen ions and oxygen vacancies inside the solid oxides. In some literature I find they are taking about the movement of negatively charged oxygen ions inside the metal oxides, while in some other cases it is...
  27. sander2798

    Calculations for shooting ions

    Hello everyone, the problem I have to solve is as following. You're in space and you're moving with a constant speed. Now, you want to accelerate. For this you will be using Newton's third law. Xenon 1+ iones will be shot from the back of the spacecraft with high speeds, the avarage speed...
  28. E

    Ions and conductivity of water

    I have studied that Ions conduct electricity in solutions due to their ability to move freely.BUT EVEN THE WATER MOLECULES MOVE FREELY, but they don't conduct electricity.What's so special in ions? I have studied the entire electrolysis process , in which the ions are attracted to the...
  29. UMath1

    Why do polyatomic ions form and how are they stabilized?

    I understand that monoatomic ions such as Sodium and Magnesium form to fill there outer shells, but why do polyatomics form? I know that CO2 is a pretty stable compound, so why does carbonate even form? Likewise what leads to the formation of ammonium?
  30. S

    Quantity of ions produced through arcing

    how would one calculate the number of ions produced per square centimeter when a continuous electrical arc is being produced between two electrodes that are separated by a meter, end in a fine point and have a voltage of 3.4 Mv? assuming standard air temperature and pressure.
  31. Metals

    Can ions separate from an ionic compound? How?

    The atoms in an ionic compound are either positively or negatively charged. I read that sodium hydroxide can cause permanent eye damage, because 'the ions travel to the back of the eyes'. Compounds are neutral, so for this to happen the ions must separate from the compound. Is this possible? If...
  32. C

    What would we percieve ions as in our eyes?

    I'm in high school and a physics novice. I have been wondering what would an object constructed of ions look like if we could see them? Is this a dumb question and there is a obvious answer I'm not thinking up for some reason?
  33. H Smith 94

    Determining number of dissociated moles from concentration?

    Is there a formula to theoretically determine the number of moles of each ion present when a particular concentration of salt is dissociated in water? I remember from A-level (high school) chemistry that concepts such as the dissociation constant exist but I'm struggling to apply them to...
  34. Carlos Gouveia

    The Salty Chemistry of Kitchen Salt in Water

    Kitchen salt is soluble in water. Whenever this happens, molecules of NaCl dissociate into the two chemical entities that form such molecule, the cation Na+ and the anion Cl-. Suppose I dissolve some amount of NaCl in water. Then I pour part of this solution into another glass. Is it...
  35. H

    Which anion could be used to selectively remove silver ions?

    The question is, which anion could be used to selectively remove silver ions from solution? The options are Cl, SO4, or CO3. All 3 of them form precipitates, but is there any that is better than the others?
  36. gracy

    Chromate and dichromate ions in equilibrium

    Homework Statement :-Why in equilibrium equation of potassium dichromate and chromate give below (in point 2.Relevant equations )there is H2O with dichromate ion but not with chromate ion, rather 2 hydrogen cation is present?[/B]Homework Equations [/B]The Attempt at a Solution :-I think it is...
  37. Teemo

    Which Isoelectronic Ions Have the Most Similar Radii?

    Homework Statement 45. Consider the ions Li+, Na+, Be2+, and Mg2+. Which two are closest to one another in size? (A) Li+ and Na+ (B) Be2+ and Mg2+ (C) Be2+ and Li+ (D) Li+ and Mg2+ Homework Equations N/A The Attempt at a Solution I thought it wouldn't be A, B, or D due to the pairs having...
  38. R

    Slab Beam of electrons through Neutralising Ions

    Homework Statement A slab beam of electrons of thickness a, width w >> a, charge density (-ρb ), (Take ρb to be positive.) and velocity vbez passes through a channel of neutralizing ions with charge density f*ρb where f is some number between zero and one (all parameters given above apply in...
  39. C

    Why are almost all polyatomic ions negative?

    or, Why are there so few polyatomic cations? What about the mechanics of an atom makes it so?
  40. H

    Fe ions in solution in a magnetic field

    I am wondering what happens when a magnetic field is applied across a solution of an iron salt (say in a beaker). Is a gradient formed? If nothing happens, why? What are the variables? Effect of oxidation state (ferrous or ferric)?
  41. D

    Calculate the number of sodium ions entering an non-myelinated axon

    Homework Statement Calculate the number of sodium ions entering a non-myelinated axon during the action potential, per metre of axon length. The change in potential is 100 mV, the axon membrane capacitance per unit length is 3 × 10−7 F/m, and the charge on an ion is 1.6 × 10−19 C. What...
  42. B

    Action Potential Through Ion Channel, Total Number of Ions Through

    Homework Statement Nerve signals in the body occur when a small voltage, called an action potential, is applied across the membrane of a cell. When this action potential is applied across a region of the cell membrane called an ion channel, current in the form of moving potassium ions will be...
  43. G

    Whats Carrying the Current in Neurons?

    I was wondering what carries the current between two nodes of ranvier (under the myelin sheath) in a neuron. Books and sources say that the impulse jumps between nodes, but I have not found one that tells me how! Is it through the membrane, across microtubules, through the cytoplasm, or...
  44. D

    Carbon ions in Tandem Accelerator

    Hi all I'm new to this forum, there seem to be quite some knowledge here. I hope someone can help shed some light on this. I took this exam about a week ago and I had no idea on how to solve this question, and I haven't been able to figure this one out since. Homework Statement In a tandem...
  45. E

    Diffusion of ions through different temperature bodies of water

    Background: I'm currently doing a research project on diffusion. I've been thinking about how soluble gases can dissolve at higher concentrations in a colder liquid than a hot liquid. Question: If there are two connected containers, one with hot water and the other with cold water, and the cold...
  46. Erland

    What neutralizes important ions in the cell?

    I am very interested in biochemistry, and in particular the metabolism of the cell. Important molecules for cell metabolism are ATP (and ADP) and NAD+ (and NADH). ATP, ADP and NAD+ are ions: ATP and ADP have negative charge (as have the free phosphate ions) and NAD+ has positive charge. But the...
  47. R

    Absorption cross sections of hydrogen ions

    hello, i need the values for the absorption cross sections of positive hydrogen ions for a specific set of wavelengths, Halpha to start with. At first i thought finding this on the web was easy, but turns out to not be trivial at all. If you can help me, i also need the (reliable) source...
  48. E

    How can I construct singlet, triplet, and more with S=1 ions?

    I've learned how to construct singlet and triplet with two S=1/2 particles, i.e., electrons. How can I generalize it to system with two S=1 ions? Furthermore, I wonder what is the general principle to make a quantum entity with n-particle S=m systems. Thank you in advance.
  49. A

    Coulomb term in Potential of ions in a Penning Trap,Green's Function

    How do you write out the potential of an ion in a Penning trap? Specifically, how does the inter-ionic Coulomb interaction come to be written as a Green's function? I found it here : http://journals.aps.org/rmp/pdf/10.1103/RevModPhys.71.87 They do say something about interactions with image...
  50. BrainMan

    Writing Ionic Formulas, Given the ions

    Homework Statement Potassium chromate is an important compound of chromium. It is composed of K+ and CrO42-. Write the formula of the compound. Homework Equations positive charge + negative charge = 0 The Attempt at a Solution I know how to do this problem by cross switching the...
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