Passage The d block metals have regular crystal structures In a regular lattice consisting of identical atoms, it is relatively easy to move the atom away from each other. There is less restriction on mobility because the electron sharing between atoms is equal. However when a second metal is added it distorts the lattice at sites where the atoms of the substituted metal reside, and this restricts atomic motions and strengthens the metal. If the disparity in sizes of the host and guest metal atoms in an alloy increases, strength of alloy (hardness) increases
Q. Which is a condition that should satisfy for the formation of alloys