I'll go with the definition of science, as I think that is what you are after. Science is an accumulation of knowledge about how the natural world works. The body of knowledge is changeable, as new discoveries are made. The knowledge is testable, in one way or another. Most of the knowledge can be applied to helping our lives become better; this applied science is known as technology.
There are specific ways the new knowledge is tested. Hypotheses (that is the plural of hypothesis) are formed; these are logical guesses. Experiments are designed so that they are ONLY testing that point--in other words, they are controlled, so that as much is the same between two sets of data, and will show only the results of what we are trying to test. See the below link for more info.
I am trying to determine if you are referring to the Periodic table that lists the elements found on earth or the key factors involved in science. I am responding to the key factors involved in science because I think this is what you are leaning towards.
Science is the study and exploration of the systems in the universe. Key components of science include but are not limited to: Identification of species and their function, exploration of physical, biological, and chemical, and universal systems. Presentation and documentation of theoretical outcomes. Enhancement of the quality of life. Protection of environments. Decreased negative effects on environments. Exploration of celestial bodies.
These are just a few key factors involved in the field of science today.
If you are leaning towards the Periodic table and the listing of the elements I have provided you with a site that lists the elements in alphabetical order. The elements listed on the periodic table are divided into alkali metals, alkaline earth metals, noble gases or inert elements, transition elements or transition metals, inner transition elements or inner transition metals, and rare earth elements.
If science has elements, at least one of them is uncertainty.