Question

Among the elements A, B, C, D having atomic numbers 9,10,11,12 respectively ,the correct order of ionization energy is:
a)A>B>C>D
b) B>A>D>C
c)B>A>c>D
d) D>C>B>A​

Answer 1

Option B is the correct answer.

• The minimum amount of energy required to remove an electron from an isolated atom or molecule is defined as ionization energy.
• As we go down the group, the values of ionization energy decrease gradually. ( Some exceptions in some groups ).
• As we go across the period, the value of ionization energy increases gradually. ( With some exceptions ).
• The elements of the 18th group have higher ionization energies compared to the other groups.
• The elements with atomic numbers 9, 10, 11, and 12 are Fluorine, Neon, Sodium, and Magnesium respectively.
• Using the properties mentioned above, the order of the ionization energies can be calculated.

=> Neon > Fluorine > Magnesium > Sodium. ( Neon is an inert gas element hence has the highest ionization energy, Magnesium lies next to Sodium in the periodic table hence Magnesium has higher ionization energy ).

=> Order of ionization energies = B > A > D > C.

Therefore, Option B is the correct answer. The correct order of the Ionization energies is B > A > D > C.