Name the transition elements of highest density.

Hint: Transition metals are located between group 2A and 3A and d – uranium elements have partially filled d – orbitals. These elements have the ability to form stable cations with an incompletely filled d – orbitals.

Complete Solution :
The transition element of highest density is OSMIUM. It belongs to the eighth group and sixth period.
The atomic number of osmium is 76 and its electronic configuration is \[\left[ Xe \right]4{{f}^{14}}5{{d}^{6}}6{{s}^{2}}\]
- The density is \[22.58g/c{{m}^{3}}\]. Osmium has a very small atomic radius and high atomic numbers. Since, density is mass per volume, the mass is packed into a very small volume. Therefore, the fractional value, which gives density is quite large.

Note: 1. The name Osmium is derived from a Greek word “Osme” meaning “smell”. It is used for producing hard alloys for foundation pen tips, needles, electrical contacts and instrument pivots. It is also known to have catalytic properties.
2. Other known transition elements include titanium, iron, cobalt, manganese, nickel, copper, silver, gold and mercury.
3. The lowest density for an element is recorded for hydrogen gas.
4. Transition metals have high density due to the metallic bonding by delocalized d – electrons. Leading to linkage or cohesion which in – turn increases with the number of shared electrons.
5. Osmium is known for extreme durability and hardness. It is a hard – bluish – white transition metal of platinum group.
6. We should remember that the term ‘transition elements’ all of which are metals, but commonly is used to denote only d – transition metals. The f – transition metals are usually called inner transition metals or rare earths.