Which of the following elements does not show allotropy?

1. Nitrogen

2. Bismuth

3. Antimony

4. Arsenic


Hint: Down the group allotropes forming tendency increases

Nitrogen does not show allotropy due to its weak N-N single bond. Therefore, the ability of nitrogen to form polymeric structures or more than one structure becomes less. Hence, nitrogen does not show allotropy.
P: White, Red and Black;
As: Yellow, Black and Gray (Grey);
Sb: White, Yellow and Black.