Which of the following represents the valence electron configuration for the helium atom?

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

Answer: (D)

Verified step by step guidance

1. Recall that the valence electron configuration refers to the electrons in the outermost shell of an atom that participate in chemical bonding.
2. Identify the atomic number of helium, which is 2, meaning it has 2 electrons in total.
3. Determine the electron configuration by filling the lowest energy orbitals first, following the Aufbau principle.
4. For helium, both electrons occupy the 1s orbital, so the electron configuration is \$1s^2$.
5. Compare the given options to this configuration and recognize that \$1s^2$ correctly represents helium's valence electron configuration.