Question

Which of the element has the highest density among transition metals?

• A. Iridium
• B. Tungsten
• C. Scandium
• D. Iron

Answer 1

The correct option is A Iridium

Down the group in d-block size doesn't increase as much because of poor shielding of f-orbitals.So,volume doesn't increase much but mass increases,hence,density increase.
Across the group in d-series,density increses due to decrease in radii and increase in atomic mass.
Hence,Iridium has the highest density among others.
Hence,option $\left(a\right)$ is correct.