[noob_]

I understand how to identify whether electronic configurations of atom show that they are ground state or excited state, however i do not understand how to identify which element they could be.
eg:
1s2 2s2 2p1 = Boron
BUT
1s2 2s2 3s2 =
or
1s2 2s2 2p6 3s1 3p1 =

My initial thought was that they are either:
How do i find what elements they could be?
Thanks.

[Borek]

In general just knowing electronic configuration and not knowing the charge you can't identify what it is.

If you assume atom is neutral, just counting electrons does the trick. If there are n electrons, and atom is neutral, how many protons are there in nucleus?

[noob_]

okay, using what you said, we would get:
carbon and magnesium respectively, if we were to estimate?

[nikium]

This might help:

You already know how to assign electron configurations to elements. You read the periodic table from left to right, filling in the right number of electrons in the exponent by counting how far you go in the row to reach the element. The electron configuration for oxygen, for example would be: 1s²2s²2p⁴.

With, 1s2 2s2 3s2, it would be carbon by virtue of its electron number, assuming a neutral element. The problem is that the orbitals are filled in the wrong order. The 2p orbital is lower energy than the 3s orbital and thus is filled first. Hence the electron configuration for carbon is: 1s²2s²2p²

Similar thing for 1s2 2s2 2p6 3s1 3p1. According to the Aufbau principle, lower energy orbitals are filled before higher energy orbitals. The configuration for Magnesium is therefore 1s²2s²2p⁶3s²

[vickium]

1s2 2s2 3s2 =

So would this be an excited Carbon, then, since 2p shell is lower in energy than the 3s shell (and it got filled first)?