The Chemical bond
Explaining chemical bonding
The Octet rule- Part III
Let's look at these examples below , Rb (37 electrons) on the left side and Br (35 electrons) on the right:
Observe the similarity with the previous example with Na and F : Rb has 1 electron in the outer shell and Br has 7 electrons in the outer shell. Because of this similarity, Rb and Br will react exactly in the same way as Na-F.
Although Rb has more electrons than Na, it also has 1 alone in the valence shell. Rb has 2 electrons in tthe 1st shell, 8 in the 2nd, 18 on the 3rd, 8 in the 4th and 1 in the 5th shell.
All the elements with a lonely electron in the outer shell react in a similar manner. That is why they are on the same group of the periodic table! That is group 1. The same apply for group 7 : 7 electrons in the valence shell.
Each group (column of the periodic table) have elements that are chemically similar.
The Octet rule also applies to the formation of covalent bonds, where electrons are shared to make chemical bonds so that molecules are formed.
This is explained in more detail in Lewis diagrams
© Ricardo Esplugas. All images in this site can be bought in an enlarged version. Please contact me on ricardochemistry@gmail.com