Which of the following represents the noble gas electron configuration for an oxygen atom?

• A. [He] 2s^2 2p^6
• B. [Ne] 2s^2 2p^4
• C. [Ne] 3s^2 3p^4
• D. [He] 2s^2 2p^4

Answer: (D)

Verified step by step guidance

1. Identify the atomic number of oxygen, which is 8. This means an oxygen atom has 8 electrons.
2. Recall that noble gas electron configurations use the electron configuration of the previous noble gas as a shorthand to represent core electrons.
3. Determine the noble gas that comes before oxygen in the periodic table. Since oxygen has 8 electrons, the noble gas before it is helium (He), which has 2 electrons.
4. Write the electron configuration for oxygen starting from helium: helium accounts for the first 2 electrons, then add the remaining 6 electrons in the 2s and 2p orbitals, resulting in 2s^2 2p^4.
5. Compare the given options to this configuration. The correct noble gas shorthand for oxygen is [He] 2s^2 2p^4.