How does the inter-particle forces help in characterising the properties of (a) potassium metal and (b) solid argon?

Explanation

To understand how inter-particle forces help in characterizing the properties of potassium metal and solid argon, we can break down the question into two parts:

### Part A: Potassium Metal

1. **Nature of Inter-particle Forces**: Potassium metal is characterized by metallic bonding. In metallic bonding, positively charged metal ions are surrounded by a sea of delocalized electrons. This allows for the conduction of electricity and heat.

2. **Properties Derived from Inter-particle Forces**:
- **Softness**: The metallic bonds in potassium are relatively weak due to the larger atomic size and the presence of only one valence electron. This results in potassium being a soft metal that can be easily cut with a knife.
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