I understand that in ionic bonding electrons are transferred from atom to atom and these ions are then attracted to each other forming a new compound. How is this different from any other transfer of charge situation? For instance, when silk and glass are rubbed together, electrons are transferred between them. These two items then attract each other but we do not say that a new chemical compound has formed, we still just have silk and glass.
$\begingroup$
$\endgroup$
3
-
$\begingroup$ Electron transmission in ionic bond is just a myth! The ionic bond is only a result of force of attraction. Rubbering silk and than detaching is result of breakage of ionic bond. $\endgroup$– Leibniz-ZJan 10 at 17:35
-
1$\begingroup$ It is matter of proportion. When you receive an electron from some material, you do not notice it. When an atom or small molecule receives an electron from another one, it is a life changing event for both. If every molecule of your body received an electron, it would lead to a coulombic explosion of gigantic proportions. $\endgroup$– PoutnikJan 10 at 19:04
-
1$\begingroup$ When silk and glas are rubbed together, the number of electrons being transferred is probably included between $10$ and $10^6$. This is enough to show the electrostatic effect. When an ionic bond is made between macroscopic amounts of $\ce{Na}$ and $\ce{Cl}$ to make up $\ce{NaCl}$, each atom reacts : the number of electrons so transferred is probably between $10^{15}$ to $10^{23}$ $\endgroup$– MauriceJan 10 at 21:35
Add a comment
|
2 Answers
$\begingroup$
$\endgroup$
Maurice's comment gives an idea of magnitude in the glass-wool-cat fur situation. It is quite different in a lightning discharge. Every transfer of electrons, if traced back far enough, involves atoms, molecules, electronic orbitals. It is just that some orbitals are of higher energy and can lose electrons more easily, but those electrons still must have somewhere to go except possibly when in flight in a cathode ray tube. That is why when you walk along a rug in winter and touch a metal post all those electrons stored in your molecules antibonding orbitals readily transfer to empty conduction bands in the metal. Physical forces as well as magnetic and electrical forces can transfer electrons among orbitals. It may be hard to analyze but that is what is happening. Some of that glass and wool is most likely chemically changed. Some of the molecules in the lightning bolt most certainly do get rearranged.
$\begingroup$
$\endgroup$
General transmission of change does not specify
- the source of the charge
- the receiver of the charge
- the amount of transmitted charge
- the distance of charge transmission
On the other hand ionic bond is partial electron transfer between adjacent atoms in contact, being bond by electrostatic force between the opposite charges.
No ionic bond is purely ionic, but is in fact partly ionic, partly covalent. As cations always more or less deform electron density of anions, decreasing the value of the electrostatic dipole.
As the rule of thumb to determine 50% of bond "ionicity" is usually considered electronegativity difference 1.7.
