Which of the following arrangements does not represent the correct order of the property stated against it ?

Which of the following arrangements does not represent the correct ord

1.	Which of the following arrangements does not represent the correct order of the property stated against it ?
Answer» `Sc ltTi lt CR lt Mn :` NUMBER of oxidation states `V^(2+) ltCr^(2+) lt Mn^(2+) lt Fe^(2+) :` paramagnetic behaviour `Ni^(2+) lt Co^(2+) lt Fe^(2+) lt Mn^(2+):` ionic size `Co^(3+) lt Fe^(3+) lt Cr^(3+) lt Sc^(3+) :` STABILITY in aqueous solution. Solution :(a) Number of oxidation states INCREASES along a period.Hence, (a) is correct. (b) `V=3d^(3) 4s^(2) , V^(2+) = 3d^(3)= 3` unpaired `e^(-)` `Cr= 3d^(5) 4s^(1) , Cr^(2+)= 3d^(4) = 4` unpaired `e^(-)` `Mn= 3d^(5)4s^(2), Mn^(2+)= 3d^(2+)= 5` unpaired `e^(-)` `Fe=3d^(6) 4s^(2), Fe^(2+)= 3d^(6) = 4` unpaired`e^(-)` Hence, correct ORDEROF paramagnetic behaviour will be `V^(2+) lt Cr^(2+) = Fe^(2) lt Mn^(2+)`. Thus, `(b)` is incorrect.(c ) Ionic radii `(M^(2+))` increase along the period . Hence, (c ) is correct. (d) Stability of `M^(3+)` ion is aqueoussoltuion increasesas `E_(M^(3+) //M^(2+))^(@)`values decrease. Hence, (d) is correct