Answer : The energy for vacancy formation in silver is, 
Explanation :
Formula used :
or,
So,
![N_v=[\frac{N_A\times \rho}{M}]\times e^{(\frac{-E}{K\times T})}](https://tex.z-dn.net/?f=N_v%3D%5B%5Cfrac%7BN_A%5Ctimes%20%5Crho%7D%7BM%7D%5D%5Ctimes%20e%5E%7B%28%5Cfrac%7B-E%7D%7BK%5Ctimes%20T%7D%29%7D)
where,
= equilibrium number of vacancies = 
E = energy = ?
M = atomic weight = 107.9 g/mole
= Avogadro's number = 
= density = 
T = temperature = 
K = Boltzmann constant = 
Now put all the given values in the above formula, we get:
![3.6\times 10^{20}L^{-1}=[\frac{(6.022\times 10^{23}mol^{-1})\times 9500g/L}{107.9g/mol}]\times e^{[\frac{-E}{(1.38\times 10^{-23}J/K)\times 1073K}]}](https://tex.z-dn.net/?f=3.6%5Ctimes%2010%5E%7B20%7DL%5E%7B-1%7D%3D%5B%5Cfrac%7B%286.022%5Ctimes%2010%5E%7B23%7Dmol%5E%7B-1%7D%29%5Ctimes%209500g%2FL%7D%7B107.9g%2Fmol%7D%5D%5Ctimes%20e%5E%7B%5B%5Cfrac%7B-E%7D%7B%281.38%5Ctimes%2010%5E%7B-23%7DJ%2FK%29%5Ctimes%201073K%7D%5D%7D)
Therefore, the energy for vacancy formation in silver is,
Answer:<em> A transfer of electrons occurs when fluorine and calcium react to form an ionic compound. This is because calcium is in group two and so forms ions with a two positive charge. ... A pairs of shared electrons makes one covalent bond. The compound formed is known as a molecule***</em>
<span>a regultate is to control or direct by a rule, principle, or method.</span>
