Why is `NF_6` compound not known?

Explanation

To understand why the compound NF₆ (Nitrogen Hexafluoride) is not known, we can break down the reasoning into several steps:

### Step 1: Determine the Electronic Configuration of Nitrogen
- Nitrogen (N) has an atomic number of 7, which means it has 7 electrons. The electronic configuration can be written as:
- 1s² 2s² 2p³

### Step 2: Analyze the Valence Electrons
- In the outermost shell (the second shell), nitrogen has 5 electrons (2 in the 2s subshell and 3 in the 2p subshell).
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