Correct order of ionisation potentials of B, C, Al, Si is:
B < Al < Si < C
B < Si < Al < C
Al < B < Si < C
Al < Si < B < C
Correct order of ionisation potentials of B, C, Al, Si is:
B < Al < Si < C
B < Si < Al < C
Al < B < Si < C
Al < Si < B < C
The correct option is D Al < Si < B < C
Ionization potential
Ionization potential is the energy required to remove the most loosely bound electron from an isolated gaseous atom. The most loosely bound electron of an atom is its valence electron which is the outermost electron. When an electron is removed from a neutral atom, a monovalent cation is obtained and the energy required for this is called the first ionization potential of the element.
The ionization energy increases across a period due to the increase in effective nuclear charge experienced by valence electron. The valence electron is more bound to the nucleus and therefore, more energy will be required for its removal. Ionization potential decreases down the group due to decrease in effective nuclear charge.
Explanation for wrong answers
(A) Boron (B) and Aluminium (Al) belong to the 13th group. Boron is in the second period and Aluminium in the third period. Since Ionization potential decreases down the group, the ionization potential of Aluminium will be less than Boron. Therefore, option (A) is incorrect.
(B) Silicon (Si) and Aluminium belong to the third period. Aluminium is in the 13th group and Silicon is in the 14th group. Since ionization potential increases across a period, Silicon will have higher ionization potential than Aluminium. Therefore, option (B) is incorrect.
(C) Boron and Silicon exhibit diagonal relationship. Therefore, they have similar ionization enthalpy. But Silicon being in the third group and Boron in the second group, the ionization enthalpy of Silicon is slightly higher than that of Boron. Therefore, option (C) is incorrect.
Explanation for correct answer
(D) Among the given four elements, Boron and Carbon (C) belong to the second period while Silicon and Aluminium belong to the third group. Therefore, the ionization enthalpies of Boron and Carbon will be higher than that of Aluminium and silicon.
Boron belongs to the 13th group and Carbon belong to the 14th group. Therefore, ionization energy of Carbon will be higher than that of Boron. Similarly, ionization enthalpy of Silicon will be greater than that of Aluminium because Silicon is in the 14th group and Aluminium is in the 13th group.
From the above observations, the order of ionization enthalpy can be given as Al < Si < B < C.
The correct option is (D) Al < Si < B < C.
Al < Si < B < C
Ionization potential
Ionization potential is the energy required to remove the most loosely bound electron from an isolated gaseous atom. The most loosely bound electron of an atom is its valence electron which is the outermost electron. When an electron is removed from a neutral atom, a monovalent cation is obtained and the energy required for this is called the first ionization potential of the element.
The ionization energy increases across a period due to the increase in effective nuclear charge experienced by valence electron. The valence electron is more bound to the nucleus and therefore, more energy will be required for its removal. Ionization potential decreases down the group due to decrease in effective nuclear charge.
Explanation for wrong answers
(A) Boron (B) and Aluminium (Al) belong to the 13th group. Boron is in the second period and Aluminium in the third period. Since Ionization potential decreases down the group, the ionization potential of Aluminium will be less than Boron. Therefore, option (A) is incorrect.
(B) Silicon (Si) and Aluminium belong to the third period. Aluminium is in the 13th group and Silicon is in the 14th group. Since ionization potential increases across a period, Silicon will have higher ionization potential than Aluminium. Therefore, option (B) is incorrect.
(C) Boron and Silicon exhibit diagonal relationship. Therefore, they have similar ionization enthalpy. But Silicon being in the third group and Boron in the second group, the ionization enthalpy of Silicon is slightly higher than that of Boron. Therefore, option (C) is incorrect.
Explanation for correct answer
(D) Among the given four elements, Boron and Carbon (C) belong to the second period while Silicon and Aluminium belong to the third group. Therefore, the ionization enthalpies of Boron and Carbon will be higher than that of Aluminium and silicon.
Boron belongs to the 13th group and Carbon belong to the 14th group. Therefore, ionization energy of Carbon will be higher than that of Boron. Similarly, ionization enthalpy of Silicon will be greater than that of Aluminium because Silicon is in the 14th group and Aluminium is in the 13th group.
From the above observations, the order of ionization enthalpy can be given as Al < Si < B < C.
The correct option is (D) Al < Si < B < C.
