What is the advantage of transition element?

Question

What is the advantage of transition element?

Answer 1

- most form multiple oxidation #s so form lost of compounds

- play central role in biology

- some are sought after & very expensive - Au, Pt etc

-  

Answer 2

they are advantageous in the sense that they form various oxidation numbers,colored ions,often used as a catalyst,used as component of alloys.

Answer 3

Your question is incomplete: advantage toward what end, and as compared to what other kind of element?  Sometimes, they *aren't* advantageous, because many transition metals can be expensive, many are toxic, many TM compounds are highly air sensitive or thermally unstable.

However, TMs have many properties that make their chemistry very different from, e.g. main group elements, and those properties can make them uniquely suited toward certain tasks.  Most of them have to do with far greater variability -- and therefore tunability -- of transition metal complex properties.  This is mostly due to the fact that TM compounds tend to have partially populated d-orbitals as their valence subshell, and these d-orbitals are relatively closely spaced together.  That means whereas an element like carbon tends to do one thing -- form four bonds, make a closed octet, exhibit limited coordination geometries and high energy changes during reactions -- a transition metal can do lots of different things, change in many different ways, and do so with relatively small energy barriers.

TM compounds can exhibit variable coordination number and geometry (e.g. complexes of Fe(II) that can have bonds to 2, 3, 4, 5, or 6 other atoms, including linear, trigonal, tetrahedral, square planar, trigonal bipyramidal, square pyramidal, octahedral, and trigonal prismatic structures), depending on how many and which d-orbitals they involve in covalent bonding.

TM compounds can exhibit variable oxidation states, with finely controlled and tunable redox potentials, because the d-orbital energies and spacings can be selectively altered with different ligands.

TM compounds exhibit different and unusual modes of bonding with organic molecules and other small main group molecular species, leading to novel reactivity modes: bonds to and reactions with "hard to react" species like H2, CH4, N2, O2 can occur readily under mild conditions when using TMs.  They can also form bonds and stabilize otherwise unstable/highly reactive organic species, and yield complexes with unusual reactivity modes (e.g. metal carbenes).

As a result, many of the highly critical reactions in both biology and industry employ TM compounds as catalysts.  Want to turn N2 into NH3?    Turn H2O into O2, H+, and an electric current?  Turn O2 into a mild, selective oxidant rather than the source of uncontrolled complete combustion?  Polymerize ethylene, propylene, or styrene into a polymer with precisely controlled structure and physical properties?   Add dihydrogen across a C=C double bond with 100% enantioselectivity?  Harness the energy of electron transfer from NADH to O2 in order to create the proton gradient necessary for the synthesis of ATP?  You need transition metals to make those reactions possible.