Give five characteristics of `d`-block elements.

Explanation

### Step-by-Step Solution

1. **Definition of d-block Elements**:
d-block elements are elements in which the last electron enters the d-orbital. They are also known as transition elements and typically have the general electronic configuration of \((n-1)d^{1-10} ns^{0-2}\), where \(n\) is the principal quantum number ranging from 4 to 7.

2. **Characteristic 1 - Physical Properties**:
d-block elements are generally hard, malleable, and ductile.
- **Hardness**: They possess a strong metallic bond, making them hard.
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