Chemistry - PERIODIC TABLE Question with Solution | TestHub
The sum of oxidation state of Fe in and Cr in is "X". Monopositive ion of an element "Y" has exactly "2X" number of electrons in ultimate shell. If the element belongs to period then number of correct orders among the following is . (i) Zn > Y (Atomic size) (ii) (iii) (iv) (number of unpaired electrons) (v) (basic nature)
Answer:
Solution:
Find : The oxidation state of Fe in K₃[Fe(CN)₆] is , and Cr in CrO₅ is (butterfly structure), so .
Identify Y: The ion Y⁺ has electrons in its outermost shell. In the 4th period, this corresponds to Copper (Cu⁺ = [Ar]3d¹⁰), meaning element Y is Cu.
Evaluate statements:
(i) is correct: Atomic size of Zn > Cu due to greater inter-electronic repulsion in the fully filled d-subshell of Zn.
(iii) is correct: First ionization energy of Cu > Ag as size increases down from the 3d to 4d transition series.
(v) is correct: Basic nature of Cu₂O > ZnO because Cu₂O is purely basic while ZnO is amphoteric.
Conclusion: Statements (ii) and (iv) are incorrect (IE₁ of Zn > Cu, and both Cu and Na have exactly 1 unpaired electron), making the total number of correct orders 3.
