Which of the following is NOT classified as an element?

Water is classified as a compound, not an element. Elements are pure substances that consist of only one type of atom and cannot be broken down into simpler substances by chemical means. Oxygen, gold, and carbon are all examples of elements; they consist of only one type of atom. Water, on the other hand, is made up of two hydrogen atoms and one oxygen atom, which means it is a compound formed by the chemical combination of different elements. This distinction is crucial in understanding the basic building blocks of matter in chemistry and the periodic table, where elements are systematically arranged based on their properties.