This method that the facets with the shortest ionization energies would be in the bottom left-hand edge of the regular table. The readjust in ionization energies is also bigger going under the periodic table (by adjust within a group) 보다 going throughout the regular table (by readjust within a period).

You are watching: Arrange the elements in order of decreasing ionization energy.

So let"s start from the bottom of the periodic table:#Pb# is the aspect that is in the lowest period at 6 (and lowest team at 14) in the periodic table; it"s the the smallest ionization energy.

The period above (5) has two the the elements: Sn and also Te. Well, since ionization energy increases throughout a period, Sn will have actually a smaller sized ionization power than Te.#Pb, Sn, Te#

Now, let"s go to the 3rd period, where #S# and also #Cl# are. Due to the fact that #S# is before #Cl,# #S# has actually a reduced ionization power than #Cl#.#Pb, Sn, Te, S, Cl#

Ernest Z.
Nov 15, 2016

The bespeak is #"Sn .

Explanation:

You have actually learned the ionization power increases from peak to bottom and from left to appropriate in the regular Table.

You more than likely saw a diagram something favor this.

Here"s the section of the regular Table that includes the elements in this question.

You would normally predict the order to be

#"Pb

This is almost correct, yet the correct order is #"Sn , as presented in the image below.

Why is this so?

The electron construction of #"Sn"# is #" 5s"^2 "4d"^10 "5p"^2#.

The electron construction of #"Pb"# is #" 6s"^2 "4f"^14 "5d"^10 "6p"^2#.

The #"4f"# electrons in #"Pb"# are bad at shielding the outermost electrons.

Thus the external electrons suffer a greater efficient nuclear charge, and also it is more challenging to remove them.

Hence #"Pb"# has a greater ionization than #"Sn"#, and also the exactly order is #"Sn .