ion

Examples of ion in the following topics:

• Ion-Dipole Force

  • The ion-dipole force is an intermolecular attraction between an ion and a polar molecule.
  • However, ion-dipole forces involve ions instead of solely polar molecules.
  • Ion-dipole forces are stronger than dipole interactions because the charge of any ion is much greater than the charge of a dipole; the strength of the ion-dipole force is proportionate to ion charge.
  • An ion-induced dipole force occurs when an ion interacts with a non-polar molecule.
  • Ion-dipole forces are generated between polar water molecules and a sodium ion.

• Lewis Structures for Polyatomic Ions

  • Lewis structures for polyatomic ions are drawn by the same methods that we have already learned.
  • When counting electrons, negative ions should have extra electrons placed in their Lewis structures; positive ions should have fewer electrons than an uncharged molecule.
  • Negative ions follow the same procedure.
  • The chlorite ion, ClO2–, contains 19 (7 from the Cl and 6 from each of the two O atoms) +1 = 20 electrons.
  • The hypochlorite ion, ClO−, contains 13 + 1 = 14 electrons.

• Characteristics of Mass Spectra

  • The highest-mass ion in a spectrum is normally considered to be the molecular ion, and lower-mass ions are fragments from the molecular ion, assuming the sample is a single pure compound.
  • The molecular ion is the strongest ion in the spectra of CO2 and C3H6, and it is moderately strong in propane.
  • The molecular ion is also the base peak, and the only fragment ions are CO (m/z=28) and O (m/z=16).
  • The molecular ion of propane also has m/z=44, but it is not the most abundant ion in the spectrum.
  • As a rule, odd-electron ions may fragment either to odd or even-electron ions, but even-electron ions fragment only to other even-electron ions.

• The Common Ion Effect

  • The common ion effect describes the changes that occur with the introduction of ions to a solution containing that same ion.
  • The common ion effect can be explained by Le Chatelier's principle of chemical equilibrium:
  • For a simple dissolution process, the addition of more of one of the ions (A+) from another compound will shift the composition to the left, reducing the concentration of the other ion (B-), effectively reducing the solubility of the solid (AB).
  • Addition of excess ions will alter the pH of the buffer solution.
  • Therefore, the common ion effect takes a role in pH regulation.

• Ion Channels

  • Ion channels are membrane proteins that allow ions to travel into or out of a cell.
  • Most channels are specific (selective) for one ion.
  • When a channel is open, ions permeate through the channel pore down the transmembrane concentration gradient for that particular ion.
  • Ion pumps are not ion channels, but are critical membrane proteins that carry out active transport by using cellular energy (ATP) to "pump" the ions against their concentration gradient.
  • A schematic representation of an ion channel.

• Chemiosmosis and Oxidative Phosphorylation

  • Chemiosmosis is the movement of ions across a selectively permeable membrane, down their electrochemical gradient.
  • The uneven distribution of H+ ions across the membrane establishes both concentration and electrical gradients (thus, an electrochemical gradient) owing to the hydrogen ions' positive charge and their aggregation on one side of the membrane.
  • If the membrane were open to diffusion by the hydrogen ions, the ions would tend to spontaneously diffuse back across into the matrix, driven by their electrochemical gradient.
  • However, many ions cannot diffuse through the nonpolar regions of phospholipid membranes without the aid of ion channels.
  • At the end of the pathway, the electrons are used to reduce an oxygen molecule to oxygen ions.

• The Lithium-Ion Battery

  • Lithium-ion batteries (Li-ion batteries, or LIBs) are a family of rechargeable batteries in which lithium ions move from the negative electrode to the positive electrode during discharge.
  • The ions follow the reverse path when the battery is charging.
  • Li-ion batteries use a lithium compound as the electrode material.
  • Lithium-ion batteries are common in consumer electronics.
  • In a lithium-ion battery, the lithium ions are transported to and from the cathode or anode.

• The Mass Spectrometer

  • The heart of the spectrometer is the ion source.
  • Some of these ions fragment into smaller cations and neutral fragments.
  • A perpendicular magnetic field deflects the ion beam in an arc whose radius is inversely proportional to the mass of each ion.
  • Lighter ions are deflected more than heavier ions.
  • Residual energy from the collision may cause the molecular ion to fragment into neutral pieces (colored green) and smaller fragment ions (colored pink and orange).

• Ionic Crystals

  • other combinations of sodium, cesium, rubidium, or lithium ions with fluoride, bromide, chloride or iodide ions
  • The exact arrangement of ions in a lattice varies according to the size of the ions in the crystal.
  • Structurally, each ion in sodium chloride is surrounded by six neighboring ions of opposite charge.
  • In CsCl, metal ions are shifted into the center of each cubic element of the Cl–-ion lattice.
  • Each cesium ion has eight nearest-neighbor chloride ions, while each chloride ion is also surrounded by eight cesium ions in (8,8) coordination.

• Formulas of Ionic Compounds

  • Its ionic formula is written as CaCl2, the neutral combination of these ions.
  • Polyatomic ions are a set of covalently bonded atoms that have an overall charge, making them an ion.
  • For example, the hydroxide ion has the formula OH-1.
  • When creating ionic compounds with these polyatomic ions, treat them the same way as typical monatomic ions (only one atom).
  • This video shows you how monoatomic ions get their charge, and how to quickly find the charge of ions by looking at the periodic table.