To determine the principal quantum number value for the highest energy electron in carbon (atomic number 6), let's go through the electronic configuration of carbon:
1. Carbon's atomic number is 6, which means it has 6 electrons.
2. The electrons are filled in the orbitals according to the Aufbau principle, which dictates the order of filling based on increasing energy levels.
Following this principle, the electron configuration for carbon is:
- 2 electrons in the 1s orbital (1s²)
- 2 electrons in the 2s orbital (2s²)
- 2 electrons in the 2p orbital (2p²)
The highest energy electrons are found in the outermost shell. In carbon, these electrons are in the 2p orbital.
- The principal quantum number (n) denotes the energy level or shell in which an electron resides.
For these highest energy electrons in the 2p orbital, the principal quantum number is:
[tex]\[ n = 2 \][/tex]
Therefore, the correct answer is:
[tex]\[ \text{B. } n=2 \][/tex]
