Alloy Formation

Transition metals form alloys easily because their atoms have similar atomic radii, which allows the atoms of one metal to replace those of another in the crystal lattice without major distortion. These substitutional solid solutions form readily when the metals have comparable sizes and similar chemical properties, producing alloys such as brass, bronze, and steel that often have superior hardness and corrosion resistance. The option of very different atomic sizes would hinder substitution and disrupt the lattice. The option of opposite charges does not apply, since alloy formation involves neutral metal atoms, not ions. The option of gaseous nature is false, as transition metals are solids with high melting points. The ease of alloy formation due to similar atomic radii is a standard NCERT d-block property. Plausibility check: the common transition-metal alloys all involve metals of comparable atomic size substituting in a shared lattice, confirming that similar sizes drive favourable alloy formation.