Consider the following statements regarding d-block elements: (I) Chromium has the maximum number of unpaired electrons in its ground state among the 3 d series elements. (II) The highest oxidation state shown by any transition element is +8 , which is exhibited by Osmium. (III) Copper is the only metal in the 3 d series with a positive standard reduction potential ( E^ _ M ²⁺/ M ). (IV) Zinc, Cadmium, and Mercury ar

Step-by-step solution

Statement (I) is correct: Chromium has the electronic configuration [ Ar ] 3 d ⁵ 4 s ¹ , giving it 6 unpaired electrons, which is the maximum in the 3 d series. Statement (II) is correct: Osmium (and Ruthenium) can exhibit an oxidation state of +8 , the highest among transition elements. Statement (III) is correct: Copper has a positive standard reduction potential ( E^ _ Cu ²⁺/ Cu = +0.34 V ), while all other 3 d series metals have negative values. Statement (IV) is incorrect: Zinc, Cadmium, and Mercury have compl