Question: How do atoms "stick together" in molecules?

Josh Meyers answered on 15 Jun 2015:

Great question! This is one of those questions that has different levels of answer depending on how complicated you want to get!

The way that atoms ‘stick-together’ is called a bond and there are many different kinds of chemical bond.

Ionic bonds occur when an atom with a negative charge (a cation) is attracted to an atom with a positive charge (an anion). In this case, the cation removes an electron from the anion. An example of this is table salt! Normal table salt is Sodium Chloride (NaCl) where Sodium is the anion (Na+) and Chloride (Cl-) is the cation.

Covalent bonds are formed between two atoms with an unstable number of electrons (electrons exist as pairs and single electrons are much less stable). By sharing electrons, two atoms can become more stable. An example of this are the bonds in Vinegar (or acetic acid).

In reality, this is a scale, there are covalent bonds with ionic character and vice versa.

Chemical bonding involves interactions between two atoms’ electrons. So we have to know where the electrons are in a molecule. This isn’t easy! Some of the most famous scientists have made their names through studying this. If you want to see something cool, check out Erwin Schrodinger and his cat. https://www.youtube.com/watch?v=IOYyCHGWJq4