Question

1. which electron configuration represents an atom in an excited state? 2 - 8 - 1 2 - 7 - 1 2 - 7 2 - 6

Explanation:

In an excited - state electron configuration, an electron has moved to a higher - energy orbital. A ground - state atom has electrons in the lowest - energy orbitals possible. The electron configuration 2 - 7 - 1 indicates that an electron has been promoted from the second shell to the third shell compared to a more stable ground - state configuration. For example, a fluorine atom in the ground state has an electron configuration of 2 - 7. When one of its electrons is excited, it can move to a higher energy level, resulting in a configuration like 2 - 7 - 1. The other configurations 2 - 8 - 1, 2 - 7, and 2 - 6 are either ground - state configurations for certain atoms or not typical excited - state configurations for common elements in this simple notation.

Answer:

2 - 7 - 1