Question

Element showing the phenomenon of allotropy is:

• A. $Al$
• B. $Pb$
• C. $Sn$
• D. $Cu$

Answer 1

The correct option is C $Sn$

Among the given elements tin ($Sn$) shows the allotropy.
β-tin (the metallic form, or white tin), which is stable at and above room temperature, is malleable. In contrast, α-tin (nonmetallic form, or gray tin), which is stable below 13.2 °C (55.8 °F), is brittle.
Hence option $C$ is correct.