Name a noble gas which has less than 8 electrons in its valence shell. What is the atomic number of this gas?

Explanation

To solve the question, we need to identify a noble gas that has less than 8 electrons in its valence shell and state its atomic number. Let's go through the steps:

### Step-by-Step Solution:

1. **Understanding Noble Gases**: Noble gases are located in Group 18 (or Group 0) of the periodic table. They are known for their stability due to having a complete valence shell, which typically contains 8 electrons (the octet rule).

2. **Identifying Noble Gases**: The noble gases include Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn).

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