Ion Definition and 406 Threads

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. T

    Common Ion Effect: pH Change for LiF, KI & NH4Cl

    Homework Statement does the ph increase , decrease or remain the same on addition of each of the folling a) LiF to an HF Solution B) KI to an HI solution C) NH4Cl to an NH3 solution Homework Equations The Attempt at a Solution i got the equations and the answers to these i just...
  2. D

    Finding Velocity of Positive ion with Volts given.

    Homework Statement An ion is accelerated through potential diff. of 250 V, directly perpendicular to mag. field. Find radius of the path of the ion in the field. Given: mass (m)=2.5 x 10^-26 charge(q)= 1.6 x 10^-19 Volts= 250 V Mag. Field (B) = 0.50 T Homework Equations...
  3. J

    Ground State Frequency of Electron in H+

    I have seen the frequency of the electron in the ground state of the hydrogen atom as 6.58 x 10^15 Hz, however I have never been able to find the ground state frequency of the electron in the hydrogen molecular ion (H+). The equilibrium separation of the two protons is given as twice the Bohr...
  4. W

    Is 1.5 Amps Too Much Current for Charging Lithium Ion Batteries?

    I have a couple of different lithium ion battery packs. On one pack charging current reads 0.1 amps, and on the other 1.5 amps. I already charged the 0.1 amp pack with 0.1 amps, and seems to be working. Now, I'm sort of weary charging the other pack with 1.5 amps. Doesn't that seem too much...
  5. M

    Electrostatic Force of Water on a Chlorine Ion

    The dipole moment of the water molecule ({\rm H}_{2}{\rm O}) is 6.17 \times 10^{-30}\;{\rm C \cdot m}. Consider a water molecule located at the origin whose dipole moment p_vec points in the positive x direction. A chlorine ion ({\rm Cl}^{-}), of charge -1.60 \times 10^{-19}\;{\rm C}, is located...
  6. L

    Understanding Fajans Rule: Ion Depletion & Valency Change

    fajans rule?? hey can anyone help me with fajans rule? after the emission of alpha rays from a radioactive substance the product remaining has a valency of 2. after the emission of beta rays it has a valency increase of 1. so the ionic depletion changes the valency. thus meaning reducing the...
  7. H

    Fluoride Ion selective electrode measurements

    Does anyone know why we prepare F- containing solutions with plastic beakers and cups instead of the regular glass beakers before measuring the responses with F- ion selective electrode Is it because F- in corrosive? where can i find infomation on this? Thanks a lot~
  8. P

    Jet + ion lifting hovering jet will it work?

    ok, I am not a physics student, engineer, or mathematician, but i have an idea i need to know will work or not. we've all undoubtedly seen star wars ep 1 with the podracer race...floating engines. would an alternator connected to a turbojet produce enough voltage to power an ion lifter? are...
  9. S

    How Does Adding Sodium Citrate Affect the pH of a Citric Acid Solution?

    What is the pH change of a 0.270 M solution of citric acid (pKa = 4.77) if enough sodium citrate is added to make the final concentration of the common citrate ion 0.145 M? Okay so first I did an ice-table using the equation: citric acid + water <--> hydronium + citric ion Using an inital...
  10. T

    Solved: Calculate Ion Concentration (27.6 g)

    [SOLVED] Ion concentration Homework Statement http://img225.imageshack.us/img225/9918/chemch0.jpg Homework Equations C = n/v The Attempt at a Solution My work is shown up above. Sorry if my work looks a little messy. My answer is 27.6 grams.
  11. C

    Ion Thruster Problem: Calculating Xenon Needed for GEO Orbit

    Homework Statement A Xenon (mass = 131 AMU) ion propulsion system has specific impulse 4920.0 sec. Calculate how much Xenon (in kg) required to maintain GEO orbit for 12 years for 8000 kg spacecraft . Assume thrust = .046 N. Calculated this to be 360 kg. Asked to find other...
  12. H

    Diverse Ion effect and Activity coefficients problem

    The question: How many grams of Ba(IO3)2 can be dissolved in 700mL of a 0.100M KIO3 solution at 25C? use activity coefficients for this. (Ksp of Ba(IO3)2 =1.57E-9) my answer: I used this equation: Ksp = (concentration) * (activity coefficient) well i found out that my ionic strength...
  13. D

    Can We Build an Ion Cannon in 5-10 Years?

    Is it possible to build an ion cannon(it's a super weapon that orbits around the Earth in space) with the technology we currently have or will have within the next 5-10 yrs?
  14. H

    How Does Potassium Nitrate Affect the Solubility of Silver Bromide?

    The question is : For AgBr at 25C, with Ksp= 5.0E-13 For KNO3 solutions: μ=0.050 γAg+ =0.8105 γBr- =0.8227 μ=0.0100 γAg+ =0.7565 γBr- =0.7794 μ=0.150 γAg+ =0.7199 γBr- =0.7529 μ=0.200 γAg+ =0.6914 γBr- =0.7340 Find the molar solubility of AgBr in 0.100-M potassium...
  15. P

    Ion Chromatography Analysis: Determining Anion Identity

    In our analytical lab we were given an unknown solution containing up to 4 anions - fluoride, chloride, nitrate, sulphate and phosphate. It was diluted, run through the chromatograph and a chromatogram was printed for 3 trials. Then we printed chromatograms for two different standard solutions...
  16. D

    Why Did the Permanganate Ion and Glucose Reaction Change Colors?

    Hi. In class recently, we performed a reaction where we added potassium permanganate solution to a solution of sodium hydroxide, followed by a few grains of glucose. The resulting solution was green for a short time, and then quickly went to an orange colour. Im not very sure about what...
  17. B

    Finding the iodide ion concentration

    Homework Statement What is the iodide ion concentration in a solution if the addition of an excess of 0.100 M Pb(NO3)2 to 37.2 mL of the solution produces 539.7 mg of PbI2? Homework Equations possibly c(1)*V(1)=c(2)*V(2) is pertinent to the problem The Attempt at a Solution I...
  18. B

    What is the concentration of Br1- ions in a solution of 0.0330% AlBr3?

    Homework Statement A solution is found to be 0.0330% by weight AlBr3. What is the concentration of the Br1- ion expressed in ppm? Homework Equations The Attempt at a Solution Assume .0330 % => .0330 g AlBr3 .0330 g AlBr3*(1 mol AlBr3/266.697 g AlBr3)*(3 mol Br^-1 /1 mol...
  19. T

    Dissolved ion distribution under the influence of an external electric field

    Hello, I'm a medical student and a few days ago a rather interesting question arose when I was doing some research. The gist of the problem is estimating how dissolved ions in a solution will distribute themselves when an external electric field is applied. Now I had basic physics and...
  20. M

    Calibration of ion flow chambre

    I need to calibrate ion flow chambre,dont know exactly how. I don't know also how to relate Bq/m3 to doserate mSv/h. Are there any doserate limits,instructions suggest that there are.
  21. S

    Complex Ion Chemistry: NH3 + Copper 2

    Hello, I have been searching for sites recently on complex ion chemistry and I have found a few good hits, but sometimes it seems the authors are vague as to the actual complex formed, and which complex actually causes the color change. For example for NH3 mixed with Copper 2, one source...
  22. J

    How Does pH Affect the Solubility of Mg(OH)2?

    Homework Statement What is the solubility of Mg(OH)2 in a solution buffered at pH 8.80.Homework Equations The Attempt at a Solution The answer is .45 M or 26 g/L but I can't get that for some reason. I can find the concentration of hydroxide [OH-] = 6.3 x 10-6 Mg(OH)2 -> Mg+2 + 2OH-...
  23. gabee

    How does a negative ion generator work?

    Like this one: http://www.goldmine-elec-products.com/prodinfo.asp?number=G9695 I understand that it uses some sort of "needle assembly," and electric fields are stronger at sharp points in a conductor and then will ionize the surrounding air at a certain potential. But how exactly are the...
  24. H

    Ion Drive Question - Ionization process

    I'm fairly familiar with the design and operation of an ion engine, although I do have a two questions in regard to its operation. 1) Normally, an ion engine would be used in space (which is naturally a vacuum) and would output its given thrust. Prior to space flight, is there a need to...
  25. L

    Hybridization and Geometry of OH- Ion

    Question: State the hybridization used and the molecular geometry shape of hydroxide ion, OH-. Okay, so I draw out the Lewis structure, where there are 6 electrons (3 lone pairs) around the O atom, which is bonded to the H atom. So, I think base on the 3 nonbonding domains and 1 bonding...
  26. M

    Titanium 2+ Ion electronic structure?

    Titanium 2+ Ion. Is it [Ar]3d^04s^2 or [Ar]3d^24s^0 I'd assume it's the former (looks more energy efficient).
  27. Y

    Calculating Hydrogen Ion Concentration & PH by Yonderboy98

    I know what the formal definition of ph is, and I am comfortable with logarithms, anti-logs, and the laws of exponents. Still, I get confused doing actual calculations and would greatly appreciate your input on the following: Suppose something has a ph of 3.5-How do you calculate the hydrogen...
  28. L

    How Does the Scanning Helium Ion Microscope Compare to Electron Microscopes?

    How is this microscope going to be way way better than the electron microscope? Does anyone know the significance of this piece of equipment? Website links would also be nice... thanks
  29. A

    Building an Ion Propulsion Unit At Home: Possible?

    i have had an idea for a few years and am finally starting to go forward with it.. i need to know if it is possible to build an ion propulsion unit at home. being that it is on the Earth and not in space does it need a defuser? can it be made to run on 110v? i don't need it huge to start. i just...
  30. S

    Atom, Ion, Particle Basics for Beginners

    wish for "simple + beginner" explanation for atom, ion and particles and their relationship. thank you.
  31. R

    Velocity of an ion given the potential difference it is accelerated through?

    I'm trying to find the mass of an unknown ion and I think the equation I'm down to to find the mass only requires me to determine the velocity before I can calculate mass -- but I don't know how. Could anyone help me out and direct me to an equation(s) that would help me find the velocity of...
  32. S

    Which Salt Produces the Lowest Carbonate Ion Concentration?

    The equilibrium constants are given for the following salts MgCO3 = 6.8x10-6 CaCO3 = 5.0x10-9 BaCO3 = 2.6x10-9 What is the name of the salt that will produce the lowest concentration of carbonate ion in solution? Write the name not the chemical formula. Is it barium carbonate?? Is...
  33. Astronuc

    Space propulsion breakthrough: new spacecraft ion engine tested

    http://www.physorg.com/news9786.html :smile:
  34. R

    Calculating Ratio of Electron and Positive Ion Mean Free Paths in an Ionised Gas

    Question goes as follows: "In an ionised gas there are positive ions and electrones moving around in collision with molecules of the gas. Calculate the ratio of the mean free path of the electrons in the gas to the mean free path of the positive ions in the gas." As far as I can see I...
  35. H

    Nucleophilicity of Acetylide ion

    I'm trying to understand the nucleophilicity of alkynes, my book lists the pKa's of acetylene (HCCH), ethylene (CH2CH2), and methane (CH3CH3) as 25, 44, and 50 respectively. This leads to the conclusion that HCCH -acetylene- is the strongest acid and hence the weakest base. The book then goes...
  36. B

    What is the method for calculating ion radii in a NaCl structure?

    Hi, I have yet another problem with this diffraction thing. I have little clue on these questions: e) The radius of the O^2- ion is assumed to be 0.126 nm. By x-ray diffraction experiments the dimensions of the unit cells for MgO, CaO, SrO and BaO has been determined to be 0.4213 nm...
  37. S

    Polyatomic Ions: Charges Explained by Chem Class

    Currently in my Chemsitry class we are reviewing these ions. Since these ions are formed of perfectly neutral elements, how can they have a charge as a whole. My teacher told me these charges in the anions can be attributed to an incomplete oxygen bond such as the negative 2 charge in carbonate(...
  38. M

    The Mystery of Copper Ion Flame Test Colors

    When I stick some Copper (II) Sulfate * Pentahyrate into the blue flame of my butane torch, it turns green. When I crush the tiny CuSO4 crystals up into a finer powder and mix them with a mixture of KClO3 and Sugar, then light that on fire, I get a very blue flame. What is happening here? I...
  39. S

    Distilled Water and Polyatomic Ion

    How would one test distilled water for sulfate ions?
  40. A

    Which Ion is More Paramagnetic?

    Why is Mn^+ more paramagnetic than N,S,Fe^+,Cr^{+2} I guess the answer would be "because it has 6 unpaired electrons" but why is that? How could I tell in advance that the one electron removed from Mn was the paired one in 4s orbital and not one of the unpaired in 3d? The Energy of 3d is...
  41. P

    Find the total charge. then decide whether you have an atom or an ion

    I don't know much about science, but I got a problem on my math homework that says "find the total charge. then decide whether you have an atom or an ion". Sodium:Electrons-10 Protons-11 Total Charge-? Atom or Ion?-? Sodium:Electrons-11...
  42. L

    Ion Sputtering: Finding Resources for Knowledge

    I meet a problem about "ion sputtering "in my work,I want to acquire some knowledge about "ion sputtering ",who can tell me where can i find relative articles? THANKS!
  43. Ivan Seeking

    Li Ion battery recharges in one minute

    Li Ion battery "recharges in one minute" http://www.eetimes.com/news/latest/showArticle.jhtml?articleID=159907938 big potential... :rolleyes:
  44. C

    Mercury Hg2+2 Ion: Why Does It Form?

    Mercury can form Hg2+2 and Hg+2 ions. Why does mercury form Hg2+2? Are there any other "diatomic ions" like this? I assume this has to do with atomic size, but why don't zinc and cadmium behave like this? They only form Zn+2 and Cd+2.
  45. T

    How Does Magnetic Force Affect an Ion Moving Along the Line x=y?

    Ok, an ion experiences a magnetic force of 6.2X10^-16 N when moving in the positive x direction, but no force when moving in the positive y direction. What is the magnitude of magnetic force exerted on the ion when it moves in the x-y plane along the line x=y? Assume the ions speed is the same...
  46. K

    What is the current density in the ion channel?

    Measurements with microelectrodes have shown that a 0.30-nm-diameter potassium ion (K+) channel carries a current of 1.8 pA. How many potassium ions pass through if the ion channel opens for 1.0 ms? What is the current density in the ion channel? I am completely lost for this one...
  47. M

    Einstein´s work ion Unified Field Theory

    I know that Einstein dedicated the end of his life working on this topic. Do anybody knows what exactly did his theory was about, and if it is connected somehow with modern unified therories? Thanks.
  48. W

    What is the Latest Advancement in Ion Drive Propellant for Deep Space Missions?

    Has arrived, eventually. http://www.sci.esa.int/science-e/www/area/index.cfm?fareaid=10 propulsion details here:http://www.sci.esa.int/science-e/www/object/index.cfm?fobjectid=34201
  49. M

    Applying Bohr's Hydrogen model to a He ion

    Hey ppl, I was wondering, with a singly ionised He atom, can we apply the Bohr model, eg E = 13.6eV/n^2, to find the energy of the excited states? How would i go about that?
  50. Z

    Acid theory - which ion does the donating?

    I understand that with an ionic acid (when in solution), either the +ve ion OR the -ve ion can be the proton donor. Are there any ways to tell which ion does the donating by just looking at the chemical structure of the acid? I'd appreciate if someone could point me in the direction of an...
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