Answer to Question #76214 in Inorganic Chemistry for Arun Rawat

Question

a). Explain the reason for the variation of the first ionization energies of the third period elements.

Answer 1

Ionization energy is the amount of energy required to remove an electron from neutral gaseous electrons.

Across period, in a periodic table from left to right ionization energy should increase.

Third period elements are:

Na, Mg, Al, Si, P, S , Cl, Ar

Order of ionization energy in third period:

Na<Mg>Al<Si<P>S<Cl<Ar

In third period element with highest ionization energy is argon due to stable octet configuration.

Case 1:

Mg has more ionization energy than Al.

Mg>Al

due too its stable ns2 configuration of Mg.

Case 2:

P has more ionization energy than sulphur (S) a because phosphorous has half filled p sub shell in its valence shell that gives extra stability and hence more energy is required to remove the electron.