The chemical element essential for the formation of DNA is phosphorus. In the structure of DNA, phosphorus is a key component of the backbone, bonding with deoxyribose sugars and helping form nucleotides. Each nucleotide, made of a sugar, a phosphate group, and a nitrogenous base, links together to create the long helical strands of DNA. This structure carries genetic information that is crucial for the growth, development, and reproduction of all living organisms. Without phosphorus, the synthesis of DNA would be impossible, underscoring its vital role in biological processes and the continuity of life.