To solve the question of which of the following is not correctly matched, we need to analyze the provided pairs based on the properties of the elements mentioned.
### Step-by-Step Solution:
1. **Identify the Elements and Their Groups/Periods**:
- The elements mentioned are boron (B), silicon (Si), carbon (C), nitrogen (N), and fluorine (F).
- Boron, carbon, nitrogen, and fluorine are in the second period of the periodic table, while silicon is in the fourth period.
2. **Understand Non-Metallic Character**:
- Non-metallic character increases from left to right across a period and decreases down a group.
- In this case, fluorine (F) is the most non-metallic, followed by nitrogen (N), carbon (C), and boron (B). Silicon (Si), being in the fourth period, has a lower non-metallic character compared to the others.
3. **Check Electronegativity**:
- Electronegativity also increases from left to right across a period and decreases down a group.
- Here, fluorine (F) has the highest electronegativity, followed by nitrogen (N), carbon (C), and boron (B). Silicon (Si) has a lower electronegativity than phosphorus (P), which is in the same group.
4. **Analyze Atomic Radius**:
- Atomic radius decreases across a period and increases down a group.
- For the halogens, fluorine (F) has the smallest atomic radius, followed by chlorine (Cl) and bromine (Br). For carbon (C) and oxygen (O), carbon is larger than oxygen.
5. **Identify the Incorrect Match**:
- Based on the analysis, we see that the order of non-metallic character is not correctly matched when silicon is included with the other non-metals (B, C, N, F). Therefore, the incorrect match is the one that includes silicon in the same category as the other non-metals.
### Conclusion:
The incorrect match is option 2, which includes silicon with the other non-metals.
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