How many types of bonds are in chemistry - Chemistry in the World - Why Is Milk White?: & 200 Other Curious Chemistry Questions (2013)

Why Is Milk White?: & 200 Other Curious Chemistry Questions (2013)

8. Chemistry in the World

How many types of bonds are in chemistry?

The first type of bond discussed in the previous answer, where the electron leaves the first atom and joins the second, is called an ionic bond. This kind of bond is found in molecules like sodium chloride (salt), where an atom that easily loses its outer electron (such as sodium) combines with an atom that has an empty slot very close to the nucleus (like chlorine) that is very good at attracting electrons.

The second type discussed, in which two nuclei share an electron, is called a covalent bond. These are very strong bonds, and they hold molecules together very well. Bonds between carbon atoms, or between carbon and hydrogen, are usually covalent bonds.

The third type of bond discussed is called a metallic bond, because it is characteristic of the bonds seen in metals.

All three of these bond types are bonds in which one or more electrons is involved. There are other kinds of bonds, usually much weaker than the first three, which form when, on average, less than a whole electron is involved.

We looked earlier at the hydrogen bond (in the discussion of water and chemistry, page 153) which forms between molecules rather than between individual atoms. Molecules are required because this kind of bond only happens when an electron spends more of its time around one atom in the molecule than around another atom. This makes one side of the molecule a little more negative and the other side a little more positive. The positive end of one molecule is then attracted to the negative end of another to make the hydrogen bond.

A similar set of effects, collectively called van der Waals forces (named after the Dutch scientist Johannes Diderik van der Waals) can happen even to single atoms. The electrons around two atoms can become correlated, so that when an electron in the first atom is on one side, so is an electron on the other atom, and when the electrons spin around the atom, they do so in synchrony, so that there is always a positive side of one atom facing the negative side of the other, creating an attraction.