ABSTRACT
In this section we introduce the chemical bonds which link atoms together to form molecules and other chemical aggregates. A slightly more advanced treatment of this topic is to be found later (see 37). In attempting to understand the various forces by which atoms are linked to each other, it is vital to keep the outline framework of atomic structure in mind (see 4), particularly the configuration of electrons (see 7). This is because chemical bonding phenomena are determined largely by the behaviour of electrons, particularly those in the outer shell of the atom. The outer shell of an atom of most of the elements is known as the valence shell. (We say ‘most’ here because for some elements the valence shell includes the underlying subshells.) Because of the key role of the valence shell, individual atoms and ions are frequently depicted by the element symbol and a number of surrounding dots which is equal to the number of electrons in the outer shell, as shown here: https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315839059/7ff28b76-deca-4052-92b5-a750b792d9b3/content/fig0001_B.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
