1. Using the Nernst equation, calculate the equilibrium potential for Ca21 and for Cl2 from the following sets of data: a. Given [Ca21]o 5 1 mM, [Ca21]i 5 100 nM, find ECa21 b. Given [Cl2]o 5 110 mM, [Cl2]i 5 10 mM, find ECl2

Answer : The value of and

Explanation :

To calculate the equilibrium potential we are using Nernst equation:

where,

 = equilibrium potential

z = valency of ion

= concentration of the ion outside the cell

= concentration of the ion inside the cell

Part a :

Given:

z = valency of ion = 2

= concentration of the ion outside the cell = 1 mM

= concentration of the ion inside the cell = 100 mM

Part b :

Given:

z = valency of ion = 1

= concentration of the ion outside the cell = 110 mM

= concentration of the ion inside the cell = 10 mM

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.