The Chemical bond
Explaining chemical bonding
The Octet rule- Part I
Explaining chemical bond is to explain why atoms bind to other atoms. Why they do that?
There is a simple rule that explain a lot of chemical bonding: it is called the octet rule.
Firstly, look at the atoms of neon (10 electrons) and kryptonium (36 electrons) below:
What do they have in common?
They have 8 electrons in their outer shells.
The outer shells of atoms are very important for chemistry. So important that they received a special name: valence shell. The valence shell is responsible for the chemical behaviour of atoms and also molecules.
Because Ne and Kr have 8 electrons in their valence shell, they are very stable. It means that they are not interested in particpating in any chemical reactions, what could change their ideal configuration. They are called noble gases because they don't get mixed with the other elements (after 1960 some reactions of the noble gases were discovered, but they are very few). All elements in this group of the periodic table have complete shells of electrons.
This is the octet rule.
It says that atoms are very stable when they have 8 electrons in their outer shell (octo- in Latin means eight-Learn more word roots). In other words, atoms are "happier" when they have 8 electrons in their outer shell. That is because nature always move spontaneously towards getting more stable , which means to go towards states of lower energy (learn more). Only living things can do otherwise.
So, what happens with elements that don't have a full valence shell?
© Ricardo Esplugas. All images in this site can be bought in an enlarged version. Please contact me on ricardochemistry@gmail.com