Following table shows the successive molar ionisation energy ( kJ mol -1) of five elements A to E. Elements Ionisation energy (KJ mol-1) I st 2 nd 3 rd 4 th A 2080 4000 6100 9400 B 500 4600 6900 9500 C 740 1500 7700 10500 D 580 1800 2700 11600 E 420 3100 4400 5900 Which two elements are most likely to be in the same group of the periodic table ?

Question

Following table shows the successive molar ionisation energy ( kJ mol -1) of five elements A to E. Elements Ionisation energy (KJ mol-1) I st 2 nd 3 rd 4 th A 2080 4000 6100 9400 B 500 4600 6900 9500 C 740 1500 7700 10500 D 580 1800 2700 11600 E 420 3100 4400 5900 Which two elements are most likely to be in the same group of the periodic table ? (A) C and D (B) D and E (C) B and D (D) B and E

Tardigrade Admin · Accepted Answer

In both B and E, after losing one electron there is sudden huge increase in ionisation energy. It means that after losing one electron, some stable configuration is achieved. So, both of them belong to the same group of the periodic table.

Elements	Ionisation energy (KJ $m o l^{- 1}$ )
Elements	I st	2 nd	3 rd	4 th
A	2080	4000	6100	9400
B	500	4600	6900	9500
C	740	1500	7700	10500
D	580	1800	2700	11600
E	420	3100	4400	5900