Question

Which of the following allotropes of silicon burns (oxidizes) in the air?

• A. Amorphous silicon
• B. Crystalline silicon
• C. Both $A$ and $B$
• D. None of the above

Answer 1

The correct option is A Amorphous silicon

Amorphous silicon, silicon in which some atoms in the structure remain unbonded, lacks long-range order, but can be produced, in principle, even more cheaply than multi-crystalline silicon. Such a lack of long-range order in the structural arrangement of the atoms is the result of what are referred to as unsatisfied, or "dangling" bonds. This isotope burns in air to produce silica ($Si{O}_2$)