Question

Which of the following is the densest metal on earth ?
a.) Rhenium
b.) Osmium
c.) Rhodium
d.) Iridium

Answer 1

Hint: The metal which has highest density belongs to Group 8. It is a transition metal with bluish-white colour. It is found as a trace element in the platinum ores. It is a rare metal. It has density twice as that of lead. It remains lustrous at high temperatures.

Complete step by step answer:
This could be a simple question for one who knows but can be the most difficult for the one who did not read about it.
Let us start with the density only.
The density of a substance can be defined as the presence of mass per unit volume of an element. Mathematically, we can write it as -
Density = ${\displaystyle \frac{Mass}{Volume}}$

Now, the most dense material. The material would have more mass per unit its volume. It would have its atoms packed very closely. Earlier the lead was considered the most dense material. It is very stable. This is the reason why lead is being used as weights and sinkers.
The Osmium is now known as the densest metal on Earth. It has a density of 22 $gc{m}^{-3}$. This density is double to that of lead.

The two major uses of Osmium compounds are-
The use of Osmium tetroxide for staining tissue in electron microscopy and it is even used during oxidation reactions of alkenes in organic chemistry.
So, the correct answer is “Option B”.

Note: The Osmium is used as alloy in electrical fittings and fountain pen nibs. It is used in places where durability and hardness is the priority. It even has low compressibility. It has a toxic nature. So, it is not used in its pure state but forms alloys with many other metal atoms. Its alloys with iridium are very hard and provide a long lasting durability.