Classification Of Elements And Periodicity In Properties Question 7
Question 7 - 31 January - Shift 2
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 $3 d$ 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 :
(1) Both (A) and (R) are true and (R) is the correct explanation of $(\mathbf{A})$
(2) Both (A) and (R) are true but (R) is not the correct explanation of (A)
(3) (A) is false but ( $\mathbf{R})$ is true
(4) (A) is true but (R) is false
Show Answer
Answer: (1)
Solution:
Formula: Ionization energy
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 |
| mathong | $Fe$ | $Co$ | $Ni$ | $Cu$ | $Zn$ |
| $IE$ $(KJ / mol)$ |
762 | 758 | 736 | 745 | 906 |
For $2^{\text{nd }}$ Group
| $Be$ | $Mg$ | $Ca$ | $Sr$ | $Ba$ | $Ra$ | |
|---|---|---|---|---|---|---|
| $IE$ $(KJ / mol)$ |
631 | 656 | 650 | 653 | 717 | 762 |
