(b) Why do transition metals form alloy ?

Explanation

### Step-by-Step Solution:

1. **Understanding Transition Metals**: Transition metals are elements found in the d-block of the periodic table. They are characterized by the presence of d electrons in their penultimate shell.

2. **Similar Atomic Radii**: One of the key reasons transition metals can form alloys is that they have similar atomic radii. This similarity allows them to mix at the atomic level without significant distortion of their crystal structures.

3. **Effect of Atomic Number**: As we move across a period in the periodic table, the atomic number increases, which means the nuclear charge (the positive charge of the nucleus) also increases. However, the number of outer shell electrons remains the same for transition metals.

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