Blake Jones
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Hi guys,

I was revising atomic spectra and so came across ground states and excitation of electrons etc.

My question is... if an electron starts in the 3rd shell for example, say the outer electron of sodium, does this count as its ground state? Because it's not the shell n=1 but it's the shell it starts in. If not, is it classed as excited because it's not in the ground state?

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MexicanKeith
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(Original post by Blake Jones)
Hi guys,

I was revising atomic spectra and so came across ground states and excitation of electrons etc.

My question is... if an electron starts in the 3rd shell for example, say the outer electron of sodium, does this count as its ground state? Because it's not the shell n=1 but it's the shell it starts in. If not, is it classed as excited because it's not in the ground state?

Thanks
You hopefully know a bit about how electrons in atoms are arranged, you should hopefully know that each orbital can hold 2 (spin paired) electrons, so not all electrons are able to exist in the n=1 level.

The ground state is the lowest energy possible state.

In sodium's ground state the 1s 2s and 2p orbitals are all filled, the lowest available orbital for the final electron is therefore the 3s.

So the ground state configuration is

1s2 2s2 2p6 3s1

because this is the lowest energy of the possible configurations.

The other configuration of Sodium you talk about would be
1s11
which is clearly impossible, you cant have 11 electrons in one orbital

(also worth noting we talk about ground states of an atom or ion, not of a single electron,
eg we wouldn't say Sodium's outer electron has a 3s ground state, we would say the sodium atom has a ground state configuration of 1s2 2s2 2p6 3s1)
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Blake Jones
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Report Thread starter 2 years ago
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(Original post by MexicanKeith)
You hopefully know a bit about how electrons in atoms are arranged, you should hopefully know that each orbital can hold 2 (spin paired) electrons, so not all electrons are able to exist in the n=1 level.

The ground state is the lowest energy possible state.

In sodium's ground state the 1s 2s and 2p orbitals are all filled, the lowest available orbital for the final electron is therefore the 3s.

So the ground state configuration is

1s2 2s2 2p6 3s1

because this is the lowest energy of the possible configurations.

The other configuration of Sodium you talk about would be
1s11
which is clearly impossible, you cant have 11 electrons in one orbital

(also worth noting we talk about ground states of an atom or ion, not of a single electron,
eg we wouldn't say Sodium's outer electron has a 3s ground state, we would say the sodium atom has a ground state configuration of 1s2 2s2 2p6 3s1)
Yeah I get that about the shells but we'd always been told it was an electron in the ground state not the atom/ion so that's what confused me I think.

Thanks
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