Simple Molecular Substances

Simple molecular substances are made up of molecules containing a few atoms joined together by covalent bonds. Here are some common examples that you should know * Hydrogen * Hydrogen atoms have just one electron. * They only need one more to complete the first shell so they often form single covalent bonds, either with other hydrogen atoms or with other elements, to achieve this. * Chlorine * Each chlorine atom needs just one more electron to complete the outer shell so two chlorine atoms can share one pair of electrons and form a single covalent bond * Oxygen * Each ocygen atom needs two more electrons to complete its outer shell so in oxygen gas two oxyegn atoms share two pairs of electrons with each other making a double covalent bond * Nitrogen * Nitrogen atoms need three more electrons so two nitrogen atoms share three pairs of electrons to fill their outer shells * This creates a triple bond * Methane * Carbon has four outer electrons, which is half a full shell * It can form four covalent bonds with hydrogen atoms to fill up its outer shell * Water * In water molecules, the oxygen shares a pair of electrons with two H atoms to form two single covalent bonds * Hydrogen Chloride * This is very similar to H2 and Cl2. * Again, both atoms only need one more electrons to complete their outer shells

Substances containing covalent bonds usually have simple molecular structures, like the examples above
The atoms within the molecules are held together by very strong covalent bonds * By contrast, the forces of attraction between these molecules are very weak