Question

Answer the following: Name the lightest and heaviest elements in terms of density among the transition elements.

Answer 1

Hint :"An element whose atom has a partly filled d subshell, or which can give birth to cations with an incomplete d subshell," according to the IUPAC definition. Any element in the d-block of the periodic table, which encompasses groups 3 to 12, is referred to as a "transition metal" by many scientists. The f-block lanthanide and actinide series are also considered transition metals and are referred to as "inner transition metals" in practise.

Complete Step By Step Answer:
Transition elements are elements with partly filled d orbitals (sometimes known as transition metals). Transition elements are defined by IUPAC as elements with a partly filled d subshell or elements that have the ability to generate stable cations with an incompletely filled d orbital. Any element that corresponds to the d-block of the contemporary periodic table (which includes groups 3-12) is considered a transition element in general. Even the lanthanides and actinides, which make up the f-block, are considered transition metals.
Colored compounds and ions are formed by these elements. The d-d electron transfer is responsible for its colour.
The energy gap between these elements' potential oxidation states is quite small. As a result, the transition elements have a wide range of oxidation states.
Because of the unpaired electrons in the d orbital, these elements generate a lot of paramagnetic compounds.
These elements can be binded by a wide range of ligands. As a result, transition elements can create a wide range of stable complexes.
These elements have a high charge-to-radius ratio.
When compared to other elements, transition metals are hard and have comparatively high densities.
Scandium (density 3.43$gc{m^-3}$) and/or iridium (density 22.59 and 22.61$gc{m^-3}$resp.) are two metals with similar densities.
The lightest transition element is Scandium (Sc). It's the first in a sequence of three-dimensional transitions. Sc has the lowest density among the transition elements.
The most dense metals are osmium and iridium. In other words, their atoms are more closely packed together in solid form than those of other metals.

Note :
The term "density" refers to the amount of mass per unit of volume. An object's average density is equal to its whole mass divided by its entire volume. An item constructed of a relatively dense material (such as iron) will have less volume than one made of a less dense substance of comparable mass (such as water).