Question

Which excited electron has the lowest energy?

A green dot in the middle of 5 concentric circles. The first away from the green dot is labeled n = 1. The second circle away from the green dot is labeled n = 2. The third circle away from the green dot is labeled n = 3. The fourth away from the green dot is labeled n = 4 and the last is labeled n = 5. There is an orange dot on the n = 5 circle.
A green dot in the middle of 5 concentric circles. The first away from the green dot is labeled n = 1. The second circle away from the green dot is labeled n = 2. The third circle away from the green dot is labeled n = 3. The fourth away from the green dot is labeled n = 4 and the last is labeled n = 5. There is an orange dot on the n = 4 circle.
A green dot in the middle of 5 concentric circles. The first away from the green dot is labeled n = 1. The second circle away from the green dot is labeled n = 2. The third circle away from the green dot is labeled n = 3. The fourth away from the green dot is labeled n = 4 and the last is labeled n = 5. There is an orange dot on the n = 3 circle.
A green dot in the middle of 5 concentric circles. The first away from the green dot is labeled n = 1. The second circle away from the green dot is labeled n = 2. The third circle away from the green dot is labeled n = 3. The fourth away from the green dot is labeled n = 4 and the last is labeled n = 5. There is an orange dot on the n = 2 circle.

Answer 1

The electron on n = 2.

Reason: atomic energy levels increase (become less negative) with n (E_n = −13.6 eV / n^2 for hydrogen), so the smallest excited level (n=2) has the lowest energy (−3.40 eV) compared with n=3,4,5.