Among the following, number of elements. Which are transition elements are :

$\mathrm{Ce},\mathrm{Nd},\mathrm{Sm},\mathrm{Yb},\mathrm{Ru},\mathrm{Th},\mathrm{U},\mathrm{Np},\mathrm{Am}$

Ru only is transition element.

In the periodic table, transition metals are situated between s-block and p-block elements. They are referred to as d-block elements. The term “transition metals” refers to the unstable and transitional behavior that these metals display between s block and p block elements.

Ruthenium is a chemical element with the symbol Ru and atomic number 44. Ruthenium, a transition metal, is a solid at ambient temperature.