Question

Zn, Cd and Hg generally are not considered as ________ elements.

Hint:

When a problem specifies "positive numbers," always reject the negative root obtained from the quadratic equation.

Answer 1

Concept:
Transition elements are defined as elements that have partially filled d-orbitals in their atoms or in at least one of their common oxidation states.
Explanation:

Zinc (Zn), Cadmium (Cd), and Mercury (Hg) belong to Group 12 of the periodic table.
Their electronic configurations have completely filled d-subshells. \[ \text{Zn}: [Ar]\,3d^{10}4s^2 \] \[ \text{Cd}: [Kr]\,4d^{10}5s^2 \] \[ \text{Hg}: [Xe]\,4f^{14}5d^{10}6s^2 \] Even in their common ions (e.g., \( \text{Zn}^{2+} \)), the d-orbitals remain fully filled.
Conclusion:
Since they do not have partially filled d-orbitals, Zn, Cd, and Hg are not considered true transition elements. \[ \boxed{\text{Answer: Transition elements}} \]