Which of the following represents the correct electron configuration for helium?

• A. 2s^2
• B. 1s^2 2s^2
• C. 1s^2
• D. 1s^1 2s^1

Answer: (C)

Verified step by step guidance

1. Recall that helium has an atomic number of 2, meaning it has 2 electrons to place in its electron configuration.
2. Understand that electrons fill orbitals starting from the lowest energy level, which is the 1s orbital.
3. Write the electron configuration by placing both electrons in the 1s orbital, since it can hold up to 2 electrons: \$1s^2$.
4. Check the other options: \$2s^2$ implies electrons in the second energy level without filling the first, which is incorrect for helium.
5. Confirm that \$1s^2 2s^2$ and \$1s^1 2s^1$ both suggest more than 2 electrons or incorrect distribution, so the correct configuration is \$1s^2$.