JEE Main2013Chemistryd and f Block ElementsActual
Which of the following arrangements does not represent the correct order of the property stated against it?
Options
- ACo 3 + < Fe 3 + < Cr 3 + < Sc 3 + : Stability in aqueous solution
- BSc < Ti < Cr < Mn : Number of oxidation states
- CV 2 + < Cr 2 + < Mn 2 + < Fe 2 + : Paramagnetic behaviour
- DNi 2 + < Co 2 + < Fe 2 + < Mn 2 + : Ionic size
Correct answer
C. V 2 + < Cr 2 + < Mn 2 + < Fe 2 + : Paramagnetic behaviour
Step-by-step solution
No. of unpaired electrons 2 3 V 2 + 1 8 Ar  4 S 0  3 d 3   =   3 2 4 Cr 2 + 1 8 Ar  4 S 0  3 d 4   =   4 2 5 Mn 2 + 1 8 Ar  4 S 0  3 d 5   =   5 2 6 Fe 2 + 1 8 Ar  4 S 0  3 d 6   =   4 On moving left to right in the periodic table, ionic size decreases. Sc shows only one oxidation state, and it is +3 but Mn shows variable oxidation state from +2 to +7.