Question
Chemistry Question on Classification of elements & periodicity in properties
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R)
Assertion (A): The first ionization enthalpy of 3d series elements is more than that of group 2 metals
Reason (R): In 3d series of elements successive filling of d-orbitals takes place
In the light of the above statements, choose the correct answer from the options given below :
Both (A) and (R) are true and (R) is the correct explanation of (A)
(A) is true but (R) is false
(A) is false but (R) is true
Both (A) and (R) are true but (R) is not the correct explanation of (A)
(A) is false but (R) is true
Solution
From Sc to Mn ionization energy is less than that of Mg.
For 3d series : | Sc | Ti | V | Cr | Mn |
---|---|---|---|---|---|
IE (KJ/mol) | 631 | 656 | 650 | 653 | 717 |
Fe | Co | Ni | Cu | Zn | |
IE (KJ/mol) | 762 | 758 | 736 | 745 | 906 |
For 2nd Group
| Be| Mg| Ca| Sr| Ba| Ra
---|---|---|---|---|---|---
IE (KJ/mol)| 631| 656| 650| 653| 717| 762
So , the correct option is (C) : (A) is false but (R) is true