State a consequence of lanthanoid contraction shown by transition elements.

Explanation

### Step-by-Step Solution

1. **Understanding Lanthanide Contraction**:
- Lanthanide contraction refers to the gradual decrease in the size of the lanthanide ions as we move from lanthanum (La) to lutetium (Lu). This occurs due to the ineffective shielding of the nuclear charge by the f-electrons.

2. **Effect on Transition Elements**:
- The lanthanide contraction affects the transition elements, particularly those in the d-block, because it leads to a decrease in the ionic radii of the elements in the same group as the lanthanides.

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