11 The graph shows the first ionization energies of some consecutive elements from Periods 2 and 3 of the Periodic Table.
The letters used to label the elements are not their chemical symbols.
(a) Which element has only one p orbital containing a pair of electrons?
(1)
A element U
B element V
C element W
D element X
ANSWER
B element V
Analysis of Option/Explanation
First of all, student should observe the graph carefully and identify the position of elements according to period and Group simultaneously.
Since in the question the examiner has mentioned that the said elements belong to period 2 and 3. Therefore we need to locate elements accordingly.
It should be remembered that as the period changes from 2 to 3 so it means that the atom is getting bigger in size i.e. one more number of shell added hence the valence electron much far away from nuclear so lower ionization energy when compared with element of same group and period changes from 2 to 3.
As per graph followed table is extracted:-
Element of Group 6 has only one paired of p orbital.
(b) Which element is the least reactive?
(1)
A element S
B element X
C element Y
D element Z
ANSWER
B element X
Analysis of Option/Explanation
Element with the greatest ionization energy is least reactive, so as per graph Element X is less reactive hence option B is the correct answer.
(c) Which element has the greatest second ionization energy?
(1)
A element S
B element T
C element X
D element Y
ANSWER
D element Y
Analysis of Option/Explanation
Remember the greatest second ionization energy will be when, there is greatest jump and this happens when shell changes. This can only be possible for group 1 element because it has one valence electron and when it is removed followed by second ionization energy so there will be shell change resulting in larger/bigger difference due to significant greater ionization energy.
Hence, the explanation suits for element Y which is option D.
