Question

How can you tell if a electron configuration is ground state or excited state?

Answer 1

You can tell which state it is in by the level that is filled (imagine a 3D atom) in an electron configuraiion of a molecule. For example, Boron has a \[1s^{2}2s^{2}2p^{1}\] That is the ground state electron configuration. If it was in the exited state, the configuration can look like this
\[1s^{2}2s^{2}2p^{2}\]
or maybe even this
\[1s^{2}2s^{2}2p^{5}\]
Basically, an element or atom in an exited state "jumps" a level, which causes a release in energy. And one can tell from the elctron configuration whether they "jumped" or not. There are many different ways to write the electron configuration of an atom in an exited sate since it depends on how many levels it jump.

Answer 2

Example :

Ground State of C : 1s2 2s2 2p2
Excited State of C : 1s2 2s1 2p3 (1 electron from 2s orbital jumped to 2p orbital which now gives 2p orbital - 3 electrons )

Answer 3

Learn more here : http://en.wikipedia.org/wiki/Excited_state

Answer 4

@Azureilai

but your configurations shows lots of excess electrons which is not true :)