The human body contains many elements from the periodic table. It is mostly composed of oxygen and carbon, but trace
elements also have a significant role. The table gives the mass, in kilograms, of some elements found in the human body, based
on a 70.0 kg person.
Atomic number
Element
Mass (kg)
8
oxygen
45.2
6
carbon
12.6
1
hydrogen
7.0
7
nitrogen
2.2
20
calcium
1.3
15
phosphorus
0.78
19
potassium
0.25
16
sulfur
0.18
others
0.60
total
70,0
Potassium makes up what fraction of the mass of the human body?