Question

The elements A, B, C and D have atomic numbers 9, 10, 11 and 12 respectively. The correct order of ionization energy is 

1) D > C > B > A 

2) A > B > C > D 

3) B > A > C > D 

4) B > A > D > C

Answer 1

4) B > A > D > C 

Element (given)	Atomic number	Element name
A	9	Fluorine
B	10	Neon
C	11	Sodium
D	12	Magnesium

B (inert gas) > A (halogen) > D (fully filled s - orbital) > C (alkali mental)