Electron Energy

[jane_ni_2d]

Why does the energy of the electron change when the hydrogen atom undergoes a transition from the 1s orbital to the 2p orbital because it says that "there are one 2s- and three 2p- orbitals in the shell and in hydrogen they all have the same energy"?

[Ashley Zhu 1A]

When an e- transitions from the 1s orbital to the 2p orbital, it is moving to a higher energy state in a different shell (from n=1 to n=2). Since the 2s and 2p orbitals are all in the same shell, they all have the same energy in a hydrogen atom due to its degenerate nature.

[dgerges 4H]

it is absorbing energy

[Sophia Fox 4B]

I think you're asking two question here. The energy changes when the electron goes from 1s to 2p because the principle quantum number, which corresponds to size and energy, is changing from n = 1 to n = 2. For hydrogen, the orbitals in a certain energy level (ie: n = 1 or n = 2 or n = 3, etc) are degenerate, meaning they all have the same energy.