Question

Tin metal exist in two allotropic forms
A. True
B. False

Answer 1

Allotrope can be defined as the one or more physical forms of a chemical element that occurs in the same physical state. Allotropes may have differences in their chemical and physical characteristics.

Complete Solution :
- Tin is a chemical substance represented by Sn having atomic number 50. It is silvery metal but soft enough to cut with a knife. It is soft, malleable, ductile and highly crystalline silvery white metal. Allotropes are various structural types of the same element so we can say that they show different physical and chemical properties. The allotropic forms change due to the same forces that influence other structures such as light, pressure and temperature. So the stability of the different allotropes depends on the specific conditions.
- Tin exists in mainly two allotropic forms named as $\alpha -tin$ and $\beta -tin$. $\alpha -tin$ exists in non-metallic form and is also known by the name gray tin. It is stable below $13.2{}^\circ C$. It has a diamond cubic structure which is similar to diamond, silicon and germanium. It shows no metallic properties because its atoms form a covalent structure due to which electrons cannot move freely. $\beta -tin$ exists in the metallic form and known by the name white tin have BCT type structure and are stable at or above room temperature. It is malleable in nature.
So, the correct answer is “Option A”.

Note: Rather than $\alpha$ and $\beta$ allotropic forms it can also exists in two other forms called $\gamma$ and $\sigma$ but these forms are only stable above $161{}^\circ C$. So these forms generally do not exist. So we consider only two allotropic forms of tin.