What is the electronic configuration of oxygen (atomic number 8)?

What is the electronic configuration of oxygen (atomic number 8)?

• A. 2,8
• B. 2,6
• C. 1,7
• D. 2,5

Answer: (B)

Electrons fill the lowest energy levels first. Oxygen has eight electrons in total, so the first shell is filled with 2 electrons, leaving 6 to go into the second shell. That gives the arrangement 2,6. This matches the total number of electrons and the capacity of the first shell. The outer shell then has six electrons, which is why oxygen tends to gain two more to reach a full octet. The other options would either sum to the wrong total or place electrons in a shell beyond its allowed capacity.

Electrons fill the lowest energy levels first. Oxygen has eight electrons in total, so the first shell is filled with 2 electrons, leaving 6 to go into the second shell. That gives the arrangement 2,6. This matches the total number of electrons and the capacity of the first shell. The outer shell then has six electrons, which is why oxygen tends to gain two more to reach a full octet. The other options would either sum to the wrong total or place electrons in a shell beyond its allowed capacity.