D Block Elements

Oxidation states will be Ti shows oxidation states of +2, +3 and +4 only. So does not exist.

Answer (c) Pd and Ag

Step 1: Understanding the Concept:
Certain transition metals exhibit polymorphism (or allotropy), meaning they can exist in more than one crystalline structure.
Step 2: Key Formula or Approach:
The approach is to recall the allotropic forms of 3d transition metals and identify which one has highly complex or multiple structures.
Step 3: Detailed Explanation:
Manganese (Mn) has a highly stable half-filled electron configuration.
Due to this stability, it exhibits complex bonding characteristics and exists in four different distinct polymorphic forms (alpha, beta, gamma, and delta).
At normal (room) temperature, it primarily exists in the -manganese form, which is a highly complex body-centered cubic structure with 58 atoms per unit cell.
Its tendency to form multiple distinct metallic structures sets it apart from typical transition metals like Cr, Ni, V, and Cu, which generally maintain a single standard bcc or fcc structure at normal conditions.
Therefore, Manganese is known for having more than one complex metallic structural form.
Step 4: Final Answer:
Mn has more than one metallic structure.