- (A) Incorrect. Zn, Cd, and Hg exhibit lower enthalpy of atomization compared to other transition metals in their respective series because they have fully filled d-subshells, which make their bonding weaker.
- (B) Correct. Zn and Cd do not show variable oxidation states, generally remaining in the \( +2 \) state. Hg, however, can show \( +1 \) and \( +2 \) oxidation states due to its unique electron configuration.
- (C) Incorrect. Compounds of Zn, Cd, and Hg are typically diamagnetic because they have fully filled d-orbitals, which do not contribute to unpaired electrons.
- (D) Correct. Zn, Cd, and Hg are known as soft metals due to their malleability and ductility.
The Correct Answer is: B, D only
Let \( T_r \) be the \( r^{\text{th}} \) term of an A.P. If for some \( m \), \( T_m = \dfrac{1}{25} \), \( T_{25} = \dfrac{1}{20} \), and \( \displaystyle\sum_{r=1}^{25} T_r = 13 \), then \( 5m \displaystyle\sum_{r=m}^{2m} T_r \) is equal to:
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): The density of the copper ($^{64}Cu$) nucleus is greater than that of the carbon ($^{12}C$) nucleus.
Reason (R): The nucleus of mass number A has a radius proportional to $A^{1/3}$.
In the light of the above statements, choose the most appropriate answer from the options given below: