how many chemical elements in the human body
Composition of the human body The average 70 kg (150 lb) adult human body contains approximately 7027700000000000000♠7×1027 atoms and contains at least detectable traces of 60 chemical elements.[3] About 29 of these elements are thought to play an active positive role in life and health in humans.[4]
Fluid balance These outputs are in balance with the input of ~2500 ml/day.[9]
Chemical substance Chemical substances exist as solids, liquids, gases, or plasma, and may change between these phases of matter with changes in temperature or pressure. Chemical substances may be combined or converted to others by means of chemical reactions.
Periodic table Each chemical element has a unique atomic number (Z) representing the number of protons in its nucleus.[n 2] Most elements have differing numbers of neutrons among different atoms, with these variants being referred to as isotopes. For example, carbon has three naturally occurring isotopes: all of its atoms have six protons and most have six neutrons as well, but about one per cent have seven neutrons, and a very small fraction have eight neutrons. Isotopes are never separated in the periodic table; they are always grouped together under a single element. Elements with no stable isotopes have the atomic masses of their most stable isotopes, where such masses are shown, listed in parentheses.[4]