Charge neutralization negative ions

An excellent apparatus for coloring crystals is the heat pipe. A detailed description of the heat pipe would be out of place in this article, but an excellent review of the method is given by Mollenauer (see Bibliography). Briefly, the heat pipe maintains a zone of pure alkali metal vapor at a precisely controlled pressure. An uncolored crystal is lowered into the alkali vapor for 30-60 min, during which time excess alkali ions diffuse into the crystal until an equilibrium is established. To maintain charge neutrality, negative ion vacancies with electrons (F-centers) must diffuse into the crystal in equal concentration. The ultimate density of F-centers in the crystal is precisely controlled by adjusting the vapor pressure. 

Hereby the initial positive ion becomes a neutral particle and the initial neutral particle becomes a new species of positive ion. The initial dilute solution must have contained sufficient negative ions to neutralize the positive charges these negative ions take no part in the reaction. As far as the ionic fields are concerned, the field of one species of positive molecular ion is replaced by that of another. 

Oxygen is 2sHp —The neutral atom has two unpaired p electrons and is therefore divalent. The gain of an electron gives a singly charged monovalent negative ion,... 

During electrolysis, the positive (usually metal) ions travel to the cathode the negative ions travel to the anode. When they reach the electrodes, the ions are discharged, i.e. they lose their charge. The negative ions give electrons away and become neutral the positive ions take in electrons and become neutral. 

Despite the apparent straightforwardness of the present techniques for determining the contribution of positive ion-molecule reactions, there is some doubt as to whether the fractions shown in Table III are as accurate as reported since they are minimum values. Charge neutralization of ions at the electrodes may give free radicals which could enhance certain products. If this is true, this contribution is not nearly as pronounced as the effect of ion-molecule reactions which decrease — G(CH4) from 7.8 with the field positive to 5.5 with the field negative. 

Ions When an atom gains or loses electrons, it becomes an ion. Positively charged ions are called cations, and negatively charged ions are called anions. Cations and anions occur together so that matter is ordinarily charge-neutral. 114 Ions Ions occur in many compounds, such as sodium chloride. 

The plasma state is often referred to as tire fourtli state of matter [1]. It is characterized by tire presence of free positive (and sometimes also negative) ions and negatively charged electrons in a neutral background gas. The... 

Enolate ions are more useful than enols for two reasons. First, pure enols can t normally be isolated but are instead generated only as short-lived intermediates in low concentration. By contrast, stable solutions of pure enolate ions are easily prepared from most carbonyl compounds by reaction with a strong base. Second, enolate ions are more reactive than enols and undergo many reactions that enols don t. Whereas enols are neutral, enolate ions are negatively charged, making them much belter nucleophiles. As a result, enolate ions are more common than enols in both laboratory and biological chemistry. 

As electrons leave the cell from the anode (electrons are released where oxidation occurs), positively charged Cu+2 ions are produced. Negative charge is leaving (by means of the electron movement) and positive charge is produced (the Cu+ ions) in this half of the cell. How is electrical neutrality maintained It must be main-... 

The first term on the right-hand side of this equation is zero, since it is simply the sum of the electrical charge in solution, which must be zero for a neutral electrolyte solution. The third term is also zero for electrolytes with equal numbers of positive and negative ions, such as NaCl and MgSC>4. It would not be zero for asymmetric electrolytes such as CaCE. However, in the Debye-Huckel approach, all terms except the second are ignored for all ionic solutions. Substitution of the resulting expression into equation (7.20) gives the linear second-order differential equation... 

The electrical double layer is the array of charged particles and/or oriented dipoles that exists at every material interface. In electrochemistry, such a layer reflects the ionic zones formed in the solution to compensate for the excess of charge on the electrode (qe). A positively charged electrode thus attracts a layer of negative ions (and vice versa). Since the interface must be neutral. qe + qs = 0 (where qs is the charge of the ions in the nearby solution). Accordingly, such a counterlayer is made... 

This species may be OH , halide ion, or any other negative ion, or it may be a neutral species with a pair to donate, in which case, of course, the immediate product must bear a positive charge (see Chapters 10, 13, 15, 16). These reactions are very fast. A recent study measured (the rate constant for reaction of a simple tertiary carbocation) to be 3.5 x 10 s . ... 

There is evidence, both experimental and theoretical, that there are intermediates in at least some Sn2 reactions in the gas phase, in charge type I reactions, where a negative ion nucleophile attacks a neutral substrate. Two energy minima, one before and one after the transition state, appear in the reaction coordinate (Fig. 10.1). The energy surface for the Sn2 Menshutkin reaction (p. 499) has been examined and it was shown that charge separation was promoted by the solvent.An ab initio study of the Sn2 reaction at primary and secondary carbon centers has looked at the energy barrier (at the transition state) to the reaction. These minima correspond to unsymmetrical ion-dipole complexes. Theoretical calculations also show such minima in certain solvents, (e.g., DMF), but not in water. "... 

Electrically charged atomic or molecular particles are called ions. When the charge is positive, the particles are cations. We do not classify electrons as ions, but when neutral atoms or molecules capture electrons, the negative ions that form are anions. 

As described in Chapter 8, ionic solids contain cations and anions strongly attracted to each other by electrical forces. These forces act between ions rather than between molecules. Ionic solids must be electrically neutral, so their stoichiometries are determined by the charges carried by the positive and negative ions. 

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