Scientific Notation

When determining electron placement in an atom there are two commonly used systems of notation. It can initially seem a little confusing but gets much easier with practice.
Since Carbon is the most abundant element in the universe we will use it in our example. The electron configuration of Carbon is:
1s2 2s2 2p2 (the second number is superscript).
To begin the notation the 1 represents the first energy level being used. The type of orbital in the first energy level is an s orbital and it contains two electrons.
The second energy level is filled next, shown by the 2 in the notation. The first orbital to receive any electrons in this level is an s orbital. The 2s orbital contains two electrons which is the maximum.
Finally the last two electrons to be placed in an atom of carbon are also in the second energy level. These electrons are placed in the first p orbital.
The total of the superscripts will always be equal to the atomic number of the element when the notation is properly written.
Since Carbon is the most abundant element in the universe we will use it in our example. The electron configuration of Carbon is:
1s2 2s2 2p2 (the second number is superscript).
To begin the notation the 1 represents the first energy level being used. The type of orbital in the first energy level is an s orbital and it contains two electrons.
The second energy level is filled next, shown by the 2 in the notation. The first orbital to receive any electrons in this level is an s orbital. The 2s orbital contains two electrons which is the maximum.
Finally the last two electrons to be placed in an atom of carbon are also in the second energy level. These electrons are placed in the first p orbital.
The total of the superscripts will always be equal to the atomic number of the element when the notation is properly written.