Which of the following d block element has half filled penultimate d sub shell as well as half filled valence sub shell?

(a)

Cr

(b)

Pd

(c)

Pt

(d)

none of these

The catalytic behaviour of transition metals and their compounds is ascribed mainly due to _______.

(a)

their magnetic behaviour

(b)

their unfilled d orbitals

(c)

their ability to adopt variable oxidation states

(d)

their chemical reactivity

The correct order of increasing oxidizing power in the series _______.

(a)

VO₂⁺ < Cr₂O₇^2- < MnO₄^-

(b)

Cr₂O₇^2- < VO₂⁺ < MnO₄^-

(c)

Cr₂O₇^2- < MnO₄^- < VO₂⁺

(d)

MnO₄^- < Cr₂O₇^2- < VO₂⁺

Which of the following statements is not true?

(a)

on passing H₂S, through acidified K₂Cr₂O₇ solution, a milky colour is observed

(b)

Na₂Cr₂O₇ is preferred over K₂Cr₂O₇ in volumetric analysis

(c)

K₂Cr₂O₇ solution in acidic medium is orange in colour

(d)

K₂Cr₂O₇ solution becomes yellow on increasing the P^H beyond 7

Permanganate ion changes to ________ in acidic medium.

(a)

MnO₄²⁻

(b)

Mn²⁺

(c)

Mn³⁺

(d)

MnO₂

What are transition metals? Give four examples.

What are actinides? Give three examples.

What is lanthanoid contraction and what are the effects of lanthanoid contraction?

Write the electronic configuration of Ce⁴⁺ and Co²⁺.

Explain the variation in E⁰_{M³⁺/M²⁺}  3d series.

Explain why Cr²⁺ is strongly reducing while Mn³⁺ is strongly oxidizing.

The E⁰_M²⁺/M value for copper is positive. Suggest a possible reason for this.

Which metal in the 3d series exhibits +1 oxidation state most frequently and why?