The atomic radii of transition elements in a period are.

Options

A. smaller than those of s-block as well as p-block elements.
B. larger than those of s-block as well as p-block elements
C. smaller than those of s-block but larger than those of p-block element
D. larger than those of s-block but smaller than those of p-block elements

Explanation

To answer the question regarding the atomic radii of transition elements in a period, we will follow a systematic approach to understand the trends in atomic radii across the periodic table, particularly focusing on the d-block elements (transition metals).

### Step-by-Step Solution:

1. **Understanding Atomic Radii Trends**:
- Atomic radii generally decrease as we move from left to right across a period in the periodic table. This is due to the increase in the effective nuclear charge (Z_eff) experienced by the valence electrons.

2. **Effective Nuclear Charge**:
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