Question

Which of the following allotropes of silicon is the most reactive?
a.) Crystalline silicon
b.) Amorphous silicon
c.) Both A and B are inert
d.) Cannot be determined.

Answer 1

Hint: Allotropy is the property of those chemical elements which can exist in two or more forms in the same physical state. In allotropes atoms of the element are bonded together in different manner.

Complete step by step answer:
Silicon is a chemical element represented by the symbol Si having atomic number 14. It is a member of group 14 in the periodic table. Electronic configuration is shown by \[1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{2}}\].
Allotropes are known as different forms of chemical elements in the same physical state in which these elements are bonded in different manners. There are two allotropes of silicon:

Crystalline silicon: Crystalline silicon also termed as polycrystalline silicon. It is a metallic grey solid substance which looks like small crystals. Crystalline silicon is stronger and more stable than amorphous silicon because the atoms in the structure are fully bonded throughout.

Amorphous silicon: It is a powdery substance which is brown in color. The atoms in the structure are mostly connected throughout, but some atoms are not bonded to their maximum capacity.
Both allotropes are inert: Inert are those substances which are not chemically reactive; both allotropes of silicon are reactive in nature so they can’t be said to be inert.
According to the above, we conclude that amorphous silicon is more reactive as compared to crystalline silicon.
So, the correct answer is “Option B”.

Note: The term allotrope refers to two or more structures made from atoms of the same element. Although the atoms within the structures are of the same element but the arrangement is different. We can consider allotropes like siblings that come from the same mother and father. They have the same DNA, but they look slightly different from one another.