Compare the general characteristics of the first series of the transition metals with those of the seconds and third series metals in the respective vertical columns. Give special emphasis on the bais of Atomic size.

Explanation

To compare the general characteristics of the first series of transition metals (3d series) with those of the second (4d series) and third (5d series) series metals in the respective vertical columns, we will focus on atomic size as a key factor.

### Step-by-Step Solution:

1. **Understanding Transition Metals**:
- Transition metals are elements that have partially filled d-orbitals. The first series includes elements from Scandium (Sc) to Zinc (Zn), the second series includes Yttrium (Y) to Cadmium (Cd), and the third series includes Hafnium (Hf) to Mercury (Hg).

2. **Atomic Size Trend**:
...