## Ground or Excited State?

MichelleTran3I
Posts: 25
Joined: Fri Sep 29, 2017 7:06 am

### Ground or Excited State?

How do you determine if an electron configuration represents the ground state or the excited state of the atom given?

Justin Chang 2K
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am

### Re: Ground or Excited State?

I'm not completely sure, but I think that if the atom is in the excited state, then the electron configuration would show an electron or two in a higher orbital (higher energy) than its ground state. For example, the electron configuration for oxygen is 1s2 2s2 2p4, which is the ground state of oxygen. If the electron configuration shows something in the third orbital or fourth orbital, I would think that means the electrons are excited and it is now in the excited state.

Seth_Evasco1L
Posts: 54
Joined: Thu Jul 27, 2017 3:00 am

### Re: Ground or Excited State?

To add on to the previous post:

An atom can also be in the excited state if the electrons don't follow Hund's Rule of filling up each empty orbital with electrons of the same spin until all orbitals are filled.

For example: (Let's look at Nitrogen) in the 2p subshell where there are 3 orbitals (Px, Py, and Pz), the ground-state configuration for nitrogen should have one electron occupying all three of the orbitals either all spin-up or spin-down (as long as they are all parallel then the spin doesn't necessarily matter). Now, if there was to be one electron that was spin-down while the other two were spin-up, that would break Hund's Rule and also be of a higher energy, thus being in an excited state. Also, if there were to be two electrons occupying one orbital and have the last one occupy a second orbital, leaving one empty, that would also break Hund's Rule and cause it to be in an excited state. This is because it takes more energy for electrons to pair in one orbital rather than have them all occupy one orbital each on their own.