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. G

    How are negative ions created in an experiment with a balloon and wool?

    In a famous experiment with a balloon and wool. http://phet.colorado.edu/sims/html/balloons-and-static-electricity/latest/balloons-and-static-electricity_en.html Initially the balloon and wool pullover have no ions. I understand how positive ions are formed, that you apply energy to the...
  2. Tclack

    Determining Charges of Polyatomic ions

    Does there exist a fool-proof way of doing it? I've scoured the forums, and I've already found this question, but the answers are not satisfying. Here for example is exactly my question: https://www.physicsforums.com/showthread.php?t=525291&highlight=polyatomic+ions I've already...
  3. Z

    Ratio of positive to negative hydrogen ions in the universe?

    Hi this may sound like a simple question but I'm trying to find out the relative abundance of hydrogen in its various forms in space: H, H+, H-, H2, H2+, H2- I'd like to know these for our stellar neighborhood involving the solar wind and also for interstellar space outside the heliopause...
  4. T

    Can atoms/ ions behave quantum mechanically at biofriendly temperature

    Can atoms/ ions/ molecules behave quantum mechanically at bio-friendly temperature? For example, cells in the human body needs around 37 degree Celsius to function properly. There are however some organisms such as Tardigrade ( which can survive for a few minutes at -273°C and for days at...
  5. R

    Why is the energy of two ions bonded lower than two ions separated?

    How does forming a bond between two ions lower the overall energy of the system? Also how would two hydrogen atoms form if there is proton-proton repulsion and electron-electron repulsion and only proton-electron attraction?
  6. M

    What kind of ions co-precipitate with chloride?

    Homework Statement Question: What kinds of ions may co-precipitate with a chloride ion? (List at least two). This is a question for the theory section of my gravimetric analysis lab. An unknown chloride salt is mixed into a solution. This solution is to be mixed with a certain quantity of...
  7. C

    Oxygen forms ions with element X

    A piece of unidentified element X reacts with oxygen to form an ionic compound with the chemical formula X2O3. Which of the following elements is the most likely identity of X? A) Ba B) Cs C) In D) P E) Zn I am doing exam practice questions...
  8. Q

    Charged ions and high pressure

    I apologize if this is the wrong category, Hello, this is my first time posting. I loved physics concepts and theories when I was younger but after taking two physics classes in college I realized that I was struggling with the math and had to give up on my dream to become a theoretical...
  9. ajayguhan

    Understanding Ion and Electron Flow in Galvanic and Electrolytic Cells

    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...
  10. R

    Calculate attractive force between Cu2+ and O2- ions.

    Homework Statement Calculate the attractive force between a pair of Cu2+ and O2- ions in the ceramic CuO that has an interatomic separation of 200pm. Homework Equations E_A= -\frac{(z_1\cdot e)(z_2\cdot e)}{4\pi\cdot\epsilon_o\cdot r} Where z_1 and z_2 are the valences of the two ion...
  11. L

    Paramagnetism of Free Ions. Sign problem.

    Energy of system of magnetic dipoles is ##E_H=-\mu_0 \vec{\mu}\cdot \vec{H}=-\mu_0\mu_zH## why sign ''-''? and ##\mu_z=-g_J\mu_Bm## Again why ''-'' sign ? ##z## is choosen to be quantization direction, and along that direction is applied field ##H##.
  12. S

    What is the best way to separate ions in water?

    What is the best way to separate ions in water? for example separating Na+ and Cl- ions from a sodium chloride water solution ( water is a ionizing solvent). is using magnets a best way or is electromagnets a best way or using Lorentz force(combination of electrical and magnetic force) a best...
  13. somasimple

    Average distance of ions in solute?

    Hi, If we know the concentration of a salt (i.e NaCl) in a solute (i.e 0.1 M), is it possible to compute an average distance (in nm) of each Na vs/ Cl ions in this solute assumed mixed?
  14. A

    Why there are so many positive and negative ions in N and P types?

    The image bellow is the PN junction under equilibrium. I wonder why there are so many positive and negative ions in N and P types respectively. For me, I think that these ions should only exist in the depeletion region not outside the region. Thanks for help.
  15. L

    Electronic configuration for ions

    When we try to predict electronic configurations by the building up principle we add electrons to the d-orbitals before the p-orbitals for principal quantum numbers n ≥ 4. What I don't understand is why, according to my textbook, we're supposed to remove electrons from np-orbitals first, then...
  16. S

    Question on why metal ions are remain stationary in the metal body

    When a metal gets polarized it looks like this: http://postimage.org/image/bkdw8ttgn/ However, only the electron moves towards the positive ion. Why is this so? As both experience an equal force despite the different accelerations, shouldn't both the positive ion and negative electron come...
  17. S

    Finding attractive force between two ions, using Coulombs equation

    Homework Statement "Calculate the force of attraction between a K + and an O 2- ion whose centers are separated by a distance of 1.5 nm." Homework Equations F = [ k (Z1)(Z2) ] / r^2 The Attempt at a Solution Both valences are filled when K is a + charge and O is a 2-...
  18. D

    Chromium Ions in Water: Balancing Cr3++ and OH- to Form Cr(OH)3

    Cr3++?OH-→ Cr(OH)3 I think it should be 9 but the mark scheme says 3 but accept correct multiples because the 3+ charge has to be canceled by 3- and this has to produce 3 O
  19. mishima

    Why do so many polyatomic ions contain oxygen?

    Why do so many polyatomic ions contain oxygen?
  20. S

    Finding Kinetic Energy of Ions Leaving a Charged Plate

    I need to know how to find the kinetic energy of ions leaving a charged plate. I figure I can find the electric potential energy, but all i know is the power being supplied to the plate and the plate's cross-sectional area. Any ideas? Thanks in advance!
  21. T

    Possible webpage title: Understanding Voltage Measurements in Biological Systems

    Hi,What is a physical principle of measuring potential on membrane? Or on body,if you measure potential of heart.I know,it sounds,like my question is nonsense.But I know,that voltmeter measure potential through free electrons.But for example if I have two clamp on body(eintohoven triangle),we...
  22. C

    Is pH Affected by Negative Ions in a Solution?

    1. If the statement ph=-log([H+] is true, then how come a solution can be acidic when carbonate is present? I have been told that even if carbonate does not accept H+ the solution will still be basic just by the presence of CO3(2-)? The confusion is this: ph only depends on [H+] then how come...
  23. M

    How Can Electric Fields Accelerate Ions in Solution?

    Hello everybody , We know it is possible to accelerate ions through electric field , this is in case of " Gas Ions " ... But , when we put some salt ( i.e : NaCl salt ) in water , we get Na+ ions and Cl- ions also , If we made a circular chamber containing this solution and applied...
  24. A

    Will gaseous ionic compounds be free moving ions?

    I knew while learning about electrolysis that if the ionic compound is molten it becomes free moving ions. If that is the case, what will happen if I continued heating till it reaches the boiling point so that the ionic compound evaporates? Will it still be free moving ions?
  25. D

    How many potassium ions pass through if the ion channel opens for 1.0 {\rm ms}?

    Homework Statement The biochemistry that takes place inside cells depends on various elements, such as sodium, potassium, and calcium, that are dissolved in water as ions. These ions enter cells through narrow pores in the cell membrane known as ion channels. Each ion channel, which is formed...
  26. W

    Born Theory - Finding the value of Z (solvation of ions)

    Homework Statement What's the energy for transfer from ε=1 to water with r=2.5Å ε=1 to water with r=5Å. Homework Equations ΔG = (1/2)*(Z^2/r)*[(1/e1)-(1/e2)] The Attempt at a Solution ΔG = (1/2)*(Z^2/2.5)*[(1/80)-(1/1)] However, I am stuck on the Z variable. Do I assume...
  27. S

    Can Ions Pass Through a Wire Like Electrons?

    Can ions pass tought a conductive wire like electrons do ?
  28. J

    Question about conductors, wires and lattice of ions

    Hi guys, sorry as this is probably a silly question. This isn't homework, but it's something I'm confused about in my GCSE course. If a lattice of ions can't conduct electricity when solid, then why can a wire (composed of these lattices (I think?)) conduct electricity? The electrons in a...
  29. Weissritter

    Self-sulfate sulfate and other ions

    First disclaimer: I do not want this for homework. I simply want an answer. Nao, what I've seen, a single halogen can get into a 0 oxidation state combining with itself. Now...could an inorganic ion have a total 0 by combining with itself? Could a SO4 join with another and create an...
  30. F

    Calculate the equilibrium concentration of hydrogen ions

    Homework Statement
  31. E

    Engineering Problems - Acceleration Required to Separate Ions

    Homework Statement I'm having trouble approaching the following problem: A research group is designing a device which will separate fast moving ions from slow moving ones. To do this, the ions are brought into the device in a narrow beam, so that all of the ions are going in the same...
  32. S

    The Electronegativity of Ions?

    Homework Statement "Rank the following in the order of increasing absolute electronegativity: F, Li, Ti4+, P, H, C, Mg2+, Li+." Homework Equations The Attempt at a Solution - I can rank neutral species no problem. Periodic table has that covered, and Pauling values are easy to...
  33. H

    Electronegativity and stability of ions?

    I've just started a course on organic chemistry and the professor said some things which did'nt exactly make sense to me: 1) In a period, atoms are more electronegative as we go to the right. The more electronegative an atom is, the more stable it becomes. 2) In a group, atoms increase...
  34. M

    Materials Science/Attraction Forces Between Ions

    Homework Statement Calculate the force of attraction between a Ca2+ and an O2- ion, the centers of which are separated by a distance of 1.25 nm.Homework Equations Attractive energy (E) = -(A/r) *The constant A is equal to (1/(4∏ε0))(Z1e)(Z2e) where ε0 is the permittivity of a vacuum (8.85 x...
  35. AGNuke

    Which ions exhibit greater stability: N vs O, P vs N, or S vs N?

    We have to determine in which of the following options, the first ion is more stable than the second. 1. 2. 3. 4. 5. 6. Attempt at the question 1. Since in the first one, +ve charge is due to bonding, not deficiency of electrons. 2. First one can get lone pair from N. 3. N...
  36. J

    Mass of ions with respect to amu

    Dear all, I have a question concerning a basic chemistry topic: atomic mass units. The current amu system defines 1 amu = 1/12 of a Carbon-12 isotope (about 1.66 * 10^-27 kg). Therefore, every other atom is assigned a amu value based upon its relationship to Carbon-12. My question...
  37. S

    Finding mass of ions in magnetic field

    A device is used to measure the charge-to-mass ratio (e/m) of ions by accelerating them using an electric field described by a potential difference , and once they have acquired kinetic energy of known amount, they enter a uniform magnetic field. The particles move in a plane perpendicular to...
  38. A

    Ions formed during Ionic Bonding

    Hi, I have a question about ions formed during ionic bonding. Is this correct? "Sodium bonds with Chlorine to form Sodium Chloride (NaCl.) Sodium loses one electron & forms a positively charged ion and Chlorine gains one & forms a negatively charged ion." If this is correct, when they...
  39. S

    Why should potassium ions leak from neurons?

    In terms of neurons, the outside is more positive than the inside. Thus, a potassium ion trying to make an escape (due to it's concentration gradient) should be deflected/repelled back into the neuron. Those ions should be bounced back in when they reach close to the surface. But since not, this...
  40. HelloCthulhu

    Can a Magnetic Field Create Ions?

    Greetings again forum! I have a question about the influence of magnetic fields on liquids. Can a magnetic field ionize a solution? If so, please explain how. Thank you!
  41. C

    Ions and Recombination: Exploring Effective Methods for Catalysts

    Is there any way to cataclyze the recombination of oppositely charged ions? I'm wondering if an effective method exists. Thanks all!
  42. R

    Several reactions involving: Chromate and Dichromate ions

    I'm not sure what: BaCrO4(s) + HNO3(aq) would yield. Would the product of this reaction be: Ba(NO3)2(aq) + H2CrO4(aq)? Or, Ba(NO3)2(aq) + H2O(l) + Cr2O7(aq) ? If so, why is this?
  43. S

    Does forming OH- ions in water base solution absorb energy

    does forming OH- ions in water base solution absorb energy ? How this mechanism works, from stable molecules to unstable ions? is this reaction endothermic or exothermic?
  44. S

    Energy of ions in different orbitals

    Homework Statement Calculate the wavelength of light needed to excite a Li2+ ion from the 4s to the 5d orbital. Report your answer with 3 significant figures. Homework Equations E=hc/lambda lambda=hc/E The Attempt at a Solution I think that the above equations are supposed to...
  45. C

    What comes out of an 'atomic oven' - atoms, ions?

    Hi, I am trying to make a Magnesium source by curling up a tungsten wire with a block of Mg inside. Then by setting electricity to the tungsten wire, the Mg is heated and you get what out? Magnesium atoms? Magnesium ions? Thanks a lot /Carnot
  46. J

    Electrolysis when multiple ions present

    What are the products of electrolysis of brine solution? At cathode i know it will be hydrogen But i am confused about the products at anode:- Either water will get oxidised or chlorine. Considering the oxidation potential values - water should get converted to oxygen but practically...
  47. E

    Magnetic Field required to seprate to ions

    Magnetic Field required two seprate to ions Homework Statement Consider a mass spectrometer used to separate the two isotopes of uranium, 238U3+ and 235U3+. Assume the ions enter the magnetic field region with a speed of 5.30X10^5 m/s. What value of B is required to give a separation of 0.6...
  48. S

    Interfering ions in a half cell

    Homework Statement The electrochemical cell: SCE // CrO4 2- (x M) / Ag2CrO4 (s) / Ag (s) is used for the determination of CrO4 2- . The standard reduction potential for the reaction: Ag2CrO4 (s) + e = 2 Ag + CrO42- is +0.446 V vs. NHE. (b) Which of the...
  49. S

    Polyatomic Ions: Formation & Reactions

    Hello all, I was reading about polyatomic ions for chem class, but in my textbook there was no description of how polyatomic ions are formed- it just states that they are a charged molecule. Are there any specific reactions that take place when a polyatomic ion is formed? For example, what...
  50. D

    Why do transition metal ions lose s electrons first?

    When transition metal start losing electrons they lose them from the s orbital before the d orbital. Why is this? The iron(II) ion has 24 electrons in this configuration: [Ar] 3d6 The neutral chromium atom also has 24 electrons, but in this configuration: [Ar] 3d5 4s1 I understand that...
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