Question

The wrong statement regarding transition metals among the following is:-

• A. Electrons enter the $(n-1)d$ orbitals after the $ns$ orbitals
• B. Atomic radii of transition metals increase rapidly with an increase in the atomic number because of poor sheilding of outer electrons by $(n-1)d$ electrons
• C. Second and third transition series elements have nearly the same size
• D. The ionisation potential of 5d transition metals are much higher than those of 3d and 4d transition metals

Answer 1

The correct option is B Atomic radii of transition metals increase rapidly with an increase in the atomic number because of poor sheilding of outer electrons by $(n-1)d$ electrons

a) Though the electrons in the $ns$ orbital go out first, they get filled before the $(n-1)d$ orbitals.
b) Due to poor sheilding of d electrons, with an increase in atomic number, $z_{eff}$ increases and the atomic radii decreases.
c) Second and third transition series elements have nearly the same size due to lanthanide contraction
d) This is because of a weak sheilding effect by the 4f electrons.