Question

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 $3 d$ 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 :

• A. Both $( A )$ and $( R )$ are true and $( R )$ is the correct explanation of $( A )$
• B. (A) is true but (R) is false
• C. (A) is false but (R) is true
• D. Both $( A )$ and $( R )$ are true but $( R )$ is not the correct explanation of $( A )$

Answer 1

Answer: (A)

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 $2^\text{nd}$ Group

	Be	Mg	Ca	Sr	Ba	Ra
IE (KJ/mol)	631	656	650	653	717	762