The following set of data display a trend. Give an explanation for the trend in terms, Ionic radius, This first ionization energy

 Question:

             The following set of data display a trend. Give an explanation for the trend in terms of the electronic structures of the ions.  Ionic radius/nm: O^2-, 0.0140; F^-, 0.133; Na⁺, 0.102; Mg²⁺, 0.072; Al³⁺, 0.053.

             Solution:

Ion	O2-	F-	Na+	Mg2+	Al3+
Ionic radius (nm)	0.140	0.133	0.102	0.072	0.053

            All the ions in this series contain ten electrons. Thus, all the ions passes the same electronic configuration such series is called iso electric series. The number of protons in the nucleus increases from O^2- to a³⁺ and due to ios electronic structure effective nuclear charge increases. Due to this increase electrons cloud contracts and is pulled more effectively by the increasing effective positive nuclear charge.

           Question:

            This first ionization energy of magnesium is greater than that of sodium but the second ionization energy of magnesium is less than that of sodium. Explain solution:

            ₁₁Mg = 15², 25², 2p⁶, 35¹

            ₁₂Mg = 15², 25², 2p⁶, 35²

           The first ionization energies of both sodium and magnesium involve the removal of electron from the 35 subshell. Since the effective nuclear charge of magnesium is greater then that of sodium that is why the first ionization energy of magnesium is higher. The 2^nd I.E of sodium involves the removal of an electron from a full and stable inner quantum shell where as the second electrons in magnesium is situated in the same sub shell as the first. Hence, a mush greater amount of energy is required to remove the second electron from a sodium un positive  ion.

            Question:

            The first four ionization energies of gallium are 579, 1979, 2963 and 6200 KJ mole^-1 respectively. Explain briefly why.

(a)              The difference between the first and second ionization energies is greater than that between the second and third ionization energies.

(b)              And the difference between the third and fourth ionization energies is greater than that between the first and second ionization energies.

(a)       Large difference between the 1^st and 2^nd ionization energies as compared to that between the second and third ionization energies shows that the first electron is removed from different sub shell i.e. p sub shell. The second and third electrons are removed from the s-subshell of the same quantum.

 

(a)              The sudden jump in ionization energies shows that the fourth electron is removed from a new inner and more stable shell. The periodic table also conferment it that Gallium is member of group III therefore it has only three valence electrons and fourth electron is present in the shell with lower quantum member.