Chemistry A Level
 

Chemical Bonding

Before A Level Chemistry, you have learned about two types of chemical bonding; ionic and covalent bonding. In A Level Chemistry, you will learn about other types of chemical bonding or how atoms can be hold together.

What is a Chemical Bond?

A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction. The strength of chemical bonds varies considerably; there are "strong bonds" such as covalent or ionic bonds and "weak bonds" such as dipole-dipole interactions, the London dispersion force (LDF) and hydrogen bonding.

Six Types of Chemical Bonding

In A Level Chemistry course, you will learn about the following types of chemical bonding in order to understand how atoms are joined together. You will learn about the electrons in the highest energy orbitals of an atom called "valency electrons".

  1. ionic bonding
  2. covalent bonding
  3. coordinate bonding
  4. hydrogen bonding
  5. dipole-dipole forces
  6. metallic bonding

Since opposite charges attract via a simple electromagnetic force, the negatively charged electrons orbiting the nucleus and the positively charged protons in the nucleus attract each other. Also, an electron positioned between two nuclei will be attracted to both of them. Thus, the most stable configuration of nuclei and electrons is one in which the electrons spend more time between nuclei, than anywhere else in space. These electrons cause the nuclei to be attracted to each other, and this attraction results in the bond. However, this assembly cannot collapse to a size dictated by the volumes of these individual particles. Due to the matter wave nature of electrons and their smaller mass, they occupy a much larger amount of volume compared with the nuclei, and this volume occupied by the electrons keeps the atomic nuclei relatively far apart, as compared with the size of the nuclei themselves.

Below is an example of Lewis dot-style chemical bonds between carbon C, hydrogen H, and oxygen O. Lewis dot depictures represent an early attempt to describe chemical bonding and are still widely used today.

Chemistry A Level chemical bonding