Simple Molecular Substances

Learn these examples of 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

Properties of simple molecular substances

• 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