Question

Following table shows the successive molar ionisation energy (kJ mol$-1$) of five elements A to E.

Element	Ionisation energy (kJ mol${}^{-1}$)
	1st	2nd	3rd	4th
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

Answer 1

The correct option is D B and E

On comparing as second ionization energy of B and E are exceptionally high, these are likely to be in the same group which is the first group. i.e. alkali metals.