What are unabbreviated and abbreviated electron configurations?

2 Answers
Apr 28, 2016

The abbreviated electron configurations uses Noble gas configurations, which have full electron shells, to describe the electronic structure of later elements.

Explanation:

He (Z=2):1s^2He(Z=2):1s2

Ne (Z=10):1s^(2)2s^(2)2p^6Ne(Z=10):1s22s22p6

Ar(Z=18):1s^(2)2s^(2)2p^(6)3s^(2)3p^6Ar(Z=18):1s22s22p63s23p6

Now we know that on the basis of these fully occupied electronic configurations, the Noble Gases are supremely unreactive. Given this inertness, and the tedium of writing out the full electronic configuration, we could write out the electronic configuration of NaNa, Z=11Z=11, for instance as [Ne]3s^1[Ne]3s1 rather than as Na:1s^(2)2s^(2)2p^(6)3s^1.Na:1s22s22p63s1.

Of course it is only the valence electrons (for instance the 3s^13s1 electron of natrium) that are involved in reaction chemistry. The inert gas core are along for the ride.

Capisce?

Apr 28, 2016

An electron configuration shows the number and arrangement of the electrons in an atom based upon the period and s,p,d,f, orbital arrangement. The abbreviate form is called Noble Gas notation.

Explanation:

An electron configuration shows the number and arrangement of the electrons in an atom based upon the period and s,p,d,f, orbital arrangement.

For instance Oxygen which has 8 elections would be

O = 1s^2 2s^2 2p^4O=1s22s22p4

Magnesium has 12 electrons

Mg = 1s^2 2s^2 2p^6 3s^2Mg=1s22s22p63s2

As we of further on the periodic table the lists would get longer and longer for instance Calcium has 20 electrons

Ca = 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2Ca=1s22s22p63s23p64s2

Typically after the 18th element Argon we can use a short hand or abbreviated version of the system by using what is referred to as Noble Gas notation.

We use the Noble gas because we know the elements electron orbital are completely full to the point.

Using Calcium again

Ca = **1s^2 2s^2 2p^6 3s^2 3p^6** 4s^2Ca=1s22s22p63s23p64s2

The bold section above is the exact same as Argon with 18 electrons

Ar = **1s^2 2s^2 2p^6 3s^2 3p^6** Ar=1s22s22p63s23p6

We can therefore replace this section with the Noble Gas Notation [Ar] in the Calcium configuration.

Ca = **[Ar]** 4s^2Ca=[Ar]4s2

We always use the Noble Gas on the row above the element we are writing the configuration for.

One more example using Silver with 47 electrons

Ag = 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3p^10 4p^6 5s^2 4d^9Ag=1s22s22p63s23p64s23p104p65s24d9

We use the Noble Gas above Silver which is Krypton [Kr]

Ag = **[Kr]** 5s^2 4d^9Ag=[Kr]5s24d9

Remember that the d block orbitals are one level lower then the period they are in on the periodic table.

Period 4 = 3d
Period 5 = 4d

etc...