Positive ion

“ An atom with an extra corpuscle is a univalent negative ion, an atom with one corpuscle detached is a univalent positive ion. In metals the electrons can slip from one atom to the next, since a current can pass without chemical action. When a current passes from an electrolyte to a metal, the electron must be detached from the atom it was accompanying and chemical action be manifested at the electrode.
Bibliography.—Michael Faraday, Experimental Researches in Electricity (London, 1844 and 1855) ”

“ Ion, ī′on, n. one of the components into which an electrolyte is broken up on electrolysis—the Anion, the electro-negative component, chemically attacking the anode, and the Cation, the electro-positive component, the cathode. ”

“ The composition of the ions, formed from the simpler of these compounds,121 may be expressed by saying that the metal component or metal-like component (hydrogen, ammonium) forms the positive ion (cation, metal ion) and all the rest of the [p070] molecule forms the negative ion (anion, acid ion122) . Thus, sodium chloride, nitrate, sulphate, phosphate yield the sodium-ion, Na+, and the chloride (Cl−) , nitrate (NO3−) , sulphate (SO42−) , or phosphate (PO43−) ions ”

“ But, on the other hand, if a few drops of acid be placed in the vessel with the platinum, bubbles of hydrogen appear, and a current flows, zinc dissolving at the anode, and hydrogen being liberated at the cathode. In order that positively electrified ions may enter a solution, an equivalent amount of other positive ions must be removed or negative ions be added, and, for the process to occur spontaneously, the possible action at the two electrodes must involve a decrease in the total available energy of the system. ”

“ Since the solution never shows the presence of an excess of either form of electricity, and the negative charge on each chloride ion is the same as on a chloride ion formed by the dissociation of hydrogen chloride, a cupric ion must hold exactly double the positive charge that a hydrogen ion does. In modern terms, each hydrogen atom, present as an ion, has lost one electron, and each copper atom present in the form of a cupric ion has lost two electrons. ”

“ The ions carry their charges with them, and, as a matter of fact, it is found that water in contact with a solution takes with respect to it a positive or negative potential, according as the positive or negative ion travels the faster. ”

“ The electrons, when they are propagated in a gas, can ionise the molecules of this gas and unite with the neutral atoms to form negative ions, while positive ions also appear. There are likewise produced, at the expense of the gas still subsisting after rarefication within the tube, positive ions which, attracted by the cathode and reaching it, are not all neutralised by the negative electrons, and can, if the cathode be perforated, pass through it, and if not, pass round it. ”

“ The potassium is much stronger than the sodium at 6rst but at higher temperatures the sodium becomes the stronger.
No great difficulty is expected in extending the investigation to all the substances found by Richardson and others to emit positive or nega- tive ions on being heated. With weak sources it will be necessary to widen the slits and be content with less resolution.
Positive Ions From Electron Bombardment It was thought that the bombardment of salts by electrons might break up the chemical compounds and give rise to many positive ions. ”

“ Further, if ions show different degrees of mobility (p. 53) , one would expect the more mobile or faster moving one to diffuse more rapidly than a less mobile ion. Such a relation should hold for the ions in a solution of hydrochloric acid, the hydrogen-ion, according to the calculations of Kohlrausch94 and the observation of Lodge,95 moving at a rate about five times as great as that of the chloride-ion, at 18°. ”

“ What gets away isn’t a sodium atom for it has one too few electrons; and what remains behind isn’t a chlorine atom for it has one too many electrons. We call these new groups “ions” from a Greek word which means “to go” for they do go, wandering off into the spaces between the water 20molecules. Fig. 3 gives you an idea of what happens.
You remember that in an atom there are always just as many protons as electrons. In this sodium ion which is formed when the nucleus of the sodium atom breaks away but leaves behind one planetary electron, there is then one more proton than there are electrons. ”

“ As the property which zinc possesses of causing the extrication of gas (under the above circumstances) has a considerable influence on the efficiency of a battery, it is well to understand thoroughly what chemical action takes place which gives rise to this evolution of gas.
§ 18. All acids may be conveniently regarded as being built up of two essential portions, viz.: firstly, a strongly electro-negative portion, which may either be a single body, such as chlorine, iodine, bromine, etc., or a compound radical, such as cyanogen; secondly, the strongly electro-positive body hydrogen. ”

“ Sometimes an ion is combined with a protein, for instance, or with other substances, and so is robbed of its own characteristics; at other times an ion is set free through decomposition or simple dissociation. ”

“ For up to this time the only type of ionization known was that observed in solution and here it is always some compound molecule like sodium chloride (NaCl) which splits up spontaneously into a positively charged sodium ion and a negatively charged chlorine ion. But the ionization produced in gases by X-rays was of a wholly different sort, for it was observable in pure gases like nitrogen or oxygen, or even in monatomic gases like argon and helium. Plainly, then, the neutral atom even of a monatomic substance must possess minute electrical charges as constituents. ”

“ We may ask, however, whether both the hydrogen atoms of carbonic acid show the same tendency to ionize, or, since there is a vast difference in the ease of ionization of different acids, whether there is not also a difference in the ease of ionization of the different hydrogen atoms in a polybasic acid. As a matter of experiment, we find that a molecule of carbonic acid does ionize, first, and more readily, into one hydrogen ion and an acid carbonate ion HCO3−, according to H2CO3 ⇄ H+ + HCO3−. ”

“ The negative ions of an electrolyte are attracted to the anode and are discharged on contact with it. Anions such as the chloride ion yield chlorine atoms, from which gaseous chlorine molecules are formed and escape. The radicals which compose such ions as NO_{3}^{-} or SO_{4}^{—} are not capable of independent existence after discharge, and break down into oxygen and N_{2}O_{5} and SO_{3} respectively. The oxygen escapes and the anhydrides, reacting with water, re-form nitric and sulphuric acids. ”

“ We would expect, then, that the potential of the hydrogen electrode must increase, when we add alkali to the solution surrounding it, the hydrogen now ionizing against a much smaller concentration of its ion. Such is in fact the case (exp.) , and the increase is found to be subject to a logarithmic function for the relation between potential and the concentration of the ion, similar to that found to hold for copper and its ion.558 In the same way, the potential of the oxygen electrode must depend on the concentration559 of the hydroxide-ion in the solution bathing it. ”

“ The + and - electric charges on the gas particles endow it
with the properties of a conductor of electricity, the + ions
moving freely in one direction and the - ions in the opposite
direction under an electric potential. But there are effects
brought about by ionisation of more importance to the medical man
than this. The chemist has long come to recognise that in the ion
he is concerned with the inner mechanism of a large number of
chemical phenomena. For with the electrification of the atom
attractive and repulsive forces arise. ”

“ In the case of non-electrolytes and of all non-ionized molecules this analogy completely represents the facts, and the phenomena of diffusion can be deduced from it alone. But the ions of an electrolytic solution can move independently through the liquid, even when no current flows, as the consequences of Ohm’s law indicate. The ions will therefore diffuse independently, and the faster ion will travel quicker into pure water in contact with a solution. ”

“ Here, then, is an absolutely direct proof that the ion must he endowed with a kinetic energy of agitation which is sufficient to push it up to the surface of the drop against the electrostatic repulsion of the charge already existing on the drop, and when we remember that an ion is nothing but a molecule containing an unneutralized electrical charge, it will be clear that we have here direct proof that the molecules of the gas are endowed with motion. ”

“ The hydrogen ions get the electrons which they need, but they get something more. They get some of the oxygen away from the plate and so form molecules of water. You remember that water molecules are made of two atoms of hydrogen and one of oxygen. Meanwhile, the lead atoms, which have lost their oxygen companions, combine with some of the sulphate ions which are in that neighborhood. During the mix-up electrons are carried away from the plate and that leaves it positive. ”

“ This indicates that there are probably no ions which have a very large number of units of excess of one kind of electricity upon them, but it gives us no information as to whether the act of ionization consists in the detachment of only one elementary electrical charge from a neutral molecule, or of two or three; for, so long as the changes are occurring when the field is off, it is impossible to distinguish between the capture of a single ion carrying two or three units of charge, and the successive capture of two or three ions each carrying the unit charge. ”

“ Inspection of the equation for acetic acid, which is the typical equilibrium equation for all monobasic acids, shows that the greater the degrees of ionization of acids are in equivalent solutions, i.e. the greater the concentrations of the hydrogen-ion which their ionization produces in equivalent solutions, the larger will be the values of their ionization constants. The acids with the larger constants are, then, the stronger acids. ”

“ On any theory of ionic charges, it seems impossible that an ion, as such, should travel in a direction against the electric forces, and we are forced to the supposition that the part of the salt which we see travelling thus is composed of non-electrolytic molecules, and is in reality attached to the opposite ion to form a complex structure which moves with the electric forces. ”

“ For the ordinary purposes of analysis, requiring the precipitation of say one milligram of any ion from 100 c.c. solution (one-tenth per cent, if one gram of substance is used for analysis) , a concentration of hydrogen-ion of 0.1 to 0.3 gram-ion per liter forms a good basis for work.421 The presence of this concentration of hydrogen-ion, irrespective of the possible presence of weak organic or inorganic acids, may be readily insured by a simple test with an appropriate indicator. ”

“ If we regard the forces which keep the atoms together as electrical in their origin, the question naturally arises, are the two atoms in a molecule of hydrogen, for example, charged one with positive the other with negative electricity; or in a molecule of hydrochloric acid gas is the hydrogen atom positively charged, the chlorine negatively, or in a compound like ammonia NH3 does the nitrogen atom carry three negative charges and each of the hydrogen atoms one positive one ? ”

“ Suggested ions for other analytes and internal standards are given in Tables 11 and 12. (8) Secondary ions may be used for quantification if the primary ion encounters interference. Secondary ions improve qualitative identification for SIM analyses. The relative abundances given are approximate (±10 to 20%) and depend upon specific instrument tuning and conditions. ”

“ The stability constants, and the concentrations of the components used, determine the limiting concentrations in which a given metal ion is capable of continued existence, and determine, therefore, the question whether an ionogen, of a given solubility, is capable of existence as a solid phase in a given system. ”

“ But if one ion, say the anion, travels faster through the liquid than the other, the end of the solution from which it comes will be more exhausted of salt than the end towards which it goes. If we assume that no other cause is at work, it is easy to prove that, with non-dissolvable electrodes, the ratio of salt lost at the anode to the salt lost at the cathode must be equal to the ratio of the velocity of the cation to the velocity of the anion. ”

“ The effect of molecular conditions in determining the sign of response to electric radiation (i.e., increase or diminution of conductivity) is exhibited by the two molecular varieties of silver, the response being positive in one case and negative in the other.
The conductivity variation is thus the expression of some molecular change. In many cases (potassium, Ag, brominated lead, etc.) we find that the change persists only during the action of radiation. On the cessation of the stimulus the substance at once shows elastic self-recovery. ”

“ You saw the test run I did for you.”
The colonel nodded. He’d watched the little chemist add an iron salt to some of the fruit juice and seen it turn red. Then he’d seen it turn pale yellow when a magnesium salt was added. “But what’s a chelating agent?” he asked.
“There are certain organic compounds,” Dr. Petrelli explained, “that are ... well, to put it simply, they’re attracted by certain ions. Some are attracted by one ion, some by another. The chelating molecules cluster around the ion and take it out of circulation, so to speak; they neutralize it, in a way. ”