> In group 15 all elements except, nitrogen and bismuth, show allotropy. ... Several allotropic forms of phosphorus are present.

Why nitrogen and bismuth do not show Allotropic forms?

Whereas all the elements in 15th group of periodic table show allotropy due to its variable oxidation state. ... Bismuth due to its inert pair effect does not exist with variable oxidation state.

Which element of Group 14 does not show allotropy?

germanium. tin allotropic form. single bonds. Hence, option (A) is the correct answer.