Now let's look at sulphur. Now, sulphur can form two, three, four or even six covalent bonds with other atoms or molecules, and also like oxygen, can form strong pi bonds, namely the double bond. So now let's look at our noble gases. Noble gases are group 18 or eight eight, and they're also known as the inner gases. Now, these guys are extremely stable and therefore, they're very unreactive. And they exist unlike every other atom or most other atoms.