Elements with outer electron configuration ns2 np6 are:

Options

A. Alkaline earth metals
B. Transition elements
C. Chalcogens
D. Noble gases

Answer

To determine which elements have the outer electron configuration of ns² np⁶, we can follow these steps:

### Step 1: Understand the Electron Configuration
The notation ns² np⁶ indicates that the outermost shell (n) has two electrons in the s subshell and six electrons in the p subshell. This configuration is characteristic of noble gases.

### Step 2: Identify the Values of n
We can substitute different values for n to find the corresponding elements:
- For n = 1: The configuration is 1s². However, there is no p subshell in the first energy level, so this corresponds to Helium (He), which is a noble gas.
- For n = 2: The configuration is 2s² 2p⁶, which corresponds to Neon (Ne), atomic number 10.
- For n = 3: The configuration is 3s² 3p⁶, which corresponds to Argon (Ar), atomic number 18.
- For n = 4: The configuration is 4s² 4p⁶, which corresponds to Krypton (Kr), atomic number 36.
- For n = 5: The configuration is 5s² 5p⁶, which corresponds to Xenon (Xe), atomic number 54.
- For n = 6: The configuration is 6s² 6p⁶, which corresponds to Radon (Rn), atomic number 86.

### Step 3: List the Elements
The elements with the outer electron configuration of ns² np⁶ are:
1. Helium (He) - n = 1
2. Neon (Ne) - n = 2
3. Argon (Ar) - n = 3
4. Krypton (Kr) - n = 4
5. Xenon (Xe) - n = 5
6. Radon (Rn) - n = 6

### Conclusion
The elements with the outer electron configuration of ns² np⁶ are the noble gases: Helium, Neon, Argon, Krypton, Xenon, and Radon.

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