Which of the following is not a transition metal?
Show Hint
- Hg
- Cu
- Ag
- Pt
The Correct Option is A
Solution and Explanation
A transition metal is defined by IUPAC as an element whose atom has an incompletely filled d-subshell, or which can give rise to cations with an incomplete d-subshell.
Step 2: Meaning
Elements with a completely filled $d^{10}$ configuration in their ground state and in their common oxidation states do not fit this definition.
Step 3: Analysis
Copper (Cu), Silver (Ag), and Platinum (Pt) exhibit common oxidation states where their d-orbitals are incompletely filled (e.g., $Cu^{2+}$ is $d^{9}$). Mercury (Hg), however, is in Group 12. Its ground state is $5d^{10} 6s^2$, and its stable oxidation states ($Hg^{2+}$) maintain a full $5d^{10}$ configuration.
Step 4: Conclusion
Since Mercury possesses completely filled d-orbitals under all standard conditions, it is not considered a true transition metal.
Final Answer: (A)
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