A non-metal that has metallic luster and sublimes on heating is? A) Chlorine B) Bromine C) Oxygen D) Iodine
Hint: We have to remember that the lustrous is a chemical property of metal, which defines a metal shine. If a metal shines it means it is lustrous whereas non-metals are no lustrous but some exceptions are there with non-metals as some of them are lustrous. Group $17$ belongs to the halogen family and group $16$ is chalcogen family.
Complete answer: Solving this question would be difficult since all of them are non-metals so we will look at the properties of each element given. Option A) this is an incorrect option as Chlorine is a yellow-green gas which has pungent and irritating odor. Sublimation occurs for solid material which directly comes into the gases phase. So chlorine is already a gas so it cannot sublimate, thus this option is incorrect. Option B) This is an incorrect option as Bromine is liquid at room temperature thus sublimation is not possible also since it is liquid it cannot have luster in it. Option C) this is an incorrect option as Oxygen is gas so it cannot sublime in heating and it has no luster in it. Option D) this is a correct option as Iodine is a solid non-metal which can be sublime into gas. It is relatively a volatile non-metal. Since iodine has intense color it has almost metallic luster in its appearance. And when iodine is heated it gives violet colored gas or you can say it sublimes to give violet gas.
Note: We need to know that the Sublimation is a process in which solid is converted directly into vapor phase than liquid phase. The material that has this property is volatile in nature. Non-metals are non-lustrous meaning they do not have shine in them but iodine being a non-metal has metallic luster.