And oxygen exists in nature in a diatomic or a triathlonic form, namely ozone or O two oxygen. Now, O two, or oxygen, reacts with metals, alkaline metals and earth metals and transition metals to form metal oxides. Now, whenever our alkaline metals react with our oxygen, they form peroxide, for example, li two or ma two, et cetera. 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.