Question

In which one of the following pairs, both the elements does not have (n-1)d¹⁰ns² configuration in its elementary state?

• A. Zn,Cd
• B. Cd,Hg
• C. Hg,Cn
• D. Cu,Zn

Answer 1

The Correct Option is D

The (n−1)d¹⁰ns² configuration is typical for transition metals in their ground state, where 'n' represents the outermost shell.

Why is option (D) correct?

• Cu (Copper): The electronic configuration of Cu is [Ar] 3d¹⁰4s¹. It does not have the (n−1)d¹⁰ns² configuration.
• Zn (Zinc): The electronic configuration of Zn is [Ar] 3d¹⁰4s². It also does not have the (n−1)d¹⁰ns² configuration.

Why are the other options incorrect?

• Option (A): Cd (Cadmium) has the configuration [Kr] 4d¹⁰5s², which fits the (n−1)d¹⁰ns² pattern.
• Option (B): Hg (Mercury) has the configuration [Xe] 4f¹⁴5d¹⁰6s², which fits the (n−1)d¹⁰ns² pattern.
• Option (C): Cn (Copernicium) is a synthetic element and its configuration is not well established, but it is likely to have a configuration that fits the (n−1)d¹⁰ns² pattern.

Conclusion: The correct answer is (D) Cu, Zn because neither copper nor zinc has the (n−1)d¹⁰ns² configuration in their elementary state.

Answer 2

The (n-1)d¹⁰ns² configuration is a characteristic feature of many transition metals in their elemental state. Let's analyze the given options: 

- Zn (Zinc): The electronic configuration of Zinc is [Ar] 3d¹⁰4s², which follows the (n-1)d¹⁰ns² configuration. 
- Cd (Cadmium): The electronic configuration of Cadmium is [Kr] 4d¹⁰5s², which also follows the (n-1)d¹⁰ns² configuration. 

Thus, both Zn and Cd have the (n-1)d¹⁰ns² configuration. 

- Cu (Copper): The electronic configuration of Copper is [Ar] 3d¹⁰4s¹, which does not strictly follow the (n-1)d¹⁰ns² configuration due to the 4s¹ configuration. 
- Zn (Zinc): As explained above, Zinc follows the (n-1)d¹⁰ns² configuration. 

Therefore, the correct pair is Cu and Zn, as Cu does not strictly follow the (n-1)d¹⁰ns² configuration in its elemental state. 

Hence, the correct answer is (D): Cu, Zn.