Question

Explain the reason for the variation of the first ionisation energies of the third period elements

Answer 1

Hi, Here is your answer

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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 I.E should increase.

Third period elements are :

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

Order of I.E 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 I.E than Al.

Mg>Al 

due too its stable ns2 configuration of Mg.

Case 2:

P has more I.E 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.

Hope it is helpful.....