The number of valence electrons present in noble gases is _______.

Explanation

To determine the number of valence electrons present in noble gases, we can follow these steps:

### Step 1: Identify Noble Gases
Noble gases are the elements found in Group 18 of the periodic table. The noble gases include:
- Helium (He)
- Neon (Ne)
- Argon (Ar)
- Krypton (Kr)
- Xenon (Xe)
- Radon (Rn)

### Step 2: Understand Valence Electrons
Valence electrons are the electrons located in the outermost shell of an atom. These electrons are important because they determine how an element reacts chemically.

### Step 3: Determine the Electron Configuration
- **Helium (He)**: Atomic number 2, electron configuration is 1s². It has 2 electrons in its outermost shell.
- **Neon (Ne)**: Atomic number 10, electron configuration is 1s² 2s² 2p⁶. It has 8 electrons in its outermost shell.
- **Argon (Ar)**: Atomic number 18, electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶. It has 8 electrons in its outermost shell.

### Step 4: Analyze the Valence Electrons
- Helium has 2 valence electrons.
- Neon has 8 valence electrons.
- Argon has 8 valence electrons.

### Step 5: Conclusion
While helium has 2 valence electrons, the other noble gases (Neon, Argon, and others) have 8 valence electrons. Therefore, in general, noble gases are known for having 8 valence electrons, which makes them stable and unreactive.

### Final Answer
The number of valence electrons present in noble gases is **8** (for all except helium, which has 2).

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