Element Mass of element in 70kg person oxygen 43 kg carbon 16 kg hydrogen 7 kg nitrogen 1.8 kg calcium 1.0 kg phosphorus 780 g potassium 140 g sulfur 140 g sodium 100 g chlorine 95 g magnesium 19 g iron 4.2 g fluorine 2.6 g zinc 2.3 g silicon 1.0 g rubidium 0.68 g strontium 0.32 g bromine 0.26 g lead 0.12 g copper 72 mg aluminum 60 mg cadmium 50 mg cerium 40 mg barium 22 mg iodine 20 mg tin 20 mg titanium 20 mg boron 18 mg nickel 15 mg selenium 15 mg chromium 14 mg manganese 12 mg arsenic 7 mg lithium 7 mg cesium 6 mg mercury 6 mg germanium 5 mg molybdenum 5 mg cobalt 3 mg antimony 2 mg silver 2 mg niobium 1.5 mg zirconium 1 mg lanthanium 0.8 mg gallium 0.7 mg tellurium 0.7 mg yttrium 0.6 mg bismuth 0.5 mg thallium 0.5 mg indium 0.4 mg gold 0.2 mg scandium 0.2 mg tantalum 0.2 mg vanadium 0.11 mg thorium 0.1 mg uranium 0.1 mg samarium 50 µg beryllium 36 µg tungsten 20 µg

Oxygen is the most abundant element in the earth's crust and in your body. The 43 kilograms of oxygen are found in the body's water (which makes up 70% of total body weight), proteins, nucleic acids, carbohydrates, and fats. Rubidium is the most abundant element in the body (0.68 g) that has no known biological role (silicon, which is slightly more abundant, may or may not have a metabolic function). Vanadium is the body's least abundant element (0.11 mg) that has a known biologic role, followed by cobalt (3 mg), which is a constituent of vitamin B12.     This number line shows the relationship between the mass units used on the table.