Question

Which of the following statements is correct about Hg?

• A. Hg is paramagnetic
• B. Hg is diamagnetic
• C. Hg is ferromagnetic
• D. Hg has unpaired electrons

Hint:

Group 12 elements (Zn, Cd, Hg) have the general configuration $(n-1)d^{10} ns^2$.
Because of their completely filled d-orbitals, they are always diamagnetic in their elemental ground states.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify the correct magnetic property of Mercury (Hg).
This is determined by checking the electronic configuration of Mercury for the presence of unpaired electrons.

Step 2: Key Formula or Approach:
We write the electronic configuration of Mercury (Hg, atomic number $Z = 80$).
We assess the filling of the subshells:
- If all electrons are paired, the substance is diamagnetic.
- If unpaired electrons are present, the substance is paramagnetic.

Step 3: Detailed Explanation:

• Mercury (Hg) is a transition element located in Group 12 and Period 6 of the periodic table, with atomic number 80.

• The complete electronic configuration of Mercury is:
\[ [\text{Xe}] \ 4f^{14} \ 5d^{10} \ 6s^2 \]

• Let us examine the outer subshells:
- The $4f$ subshell is fully filled with 14 electrons.
- The $5d$ subshell is fully filled with 10 electrons.
- The $6s$ subshell is fully filled with 2 electrons.

• Because every single atomic orbital in Mercury is completely filled, there are zero unpaired electrons.

• In the absence of unpaired electrons, the magnetic fields of the individual electron spins cancel each other out.

• Therefore, Mercury is weakly repelled by an external magnetic field, which is the defining characteristic of a diamagnetic substance.

• Since it has no unpaired electrons, options (A), (C), and (D) are incorrect.


Step 4: Final Answer:
Thus, Hg is diamagnetic due to its fully filled d and s subshells.