|
Element
| Symbol
| %
in Earth's Crust (by wt.)
| %
in Human Body (by wt.)
| Importance
or Function |
|---|
Oxygen
|
O
|
47
|
65
|
disposes
of electrons in respiration; contributes to water solubility in molecules
|
Silicon
|
Si
|
28
|
Trace
|
--
|
Aluminum
|
Al
|
6
|
Trace
|
--
|
Iron
|
Fe
|
5
|
Trace
|
used
in respiratory pigments
|
Calcium
|
Ca
|
4
|
1.5
|
component
of bones & teeth; triggers muscle contraction
|
Sodium
|
Na
|
3
|
0.2
|
used
in nerve conduction
|
Potassium
|
K
|
3
|
0.4
|
used
in nerve conduction; needed by many enzymes
|
Magnesium
|
Mg
|
2
|
0.1
|
critical
part of many energy-transferring enzymes
|
| Hydrogen
|
H
|
0.14
|
9.5
|
electron
carrier; major component of organic molecules
|
Manganese
|
Mn
|
0.1
|
Trace
|
--
|
Fluorine
|
F
|
0.07
|
Trace
|
--
|
Phosphorus
|
P
|
0.07
|
1.0
|
backbone
of nucleic acids; important in energy transfer
|
Carbon
|
C
|
0.03
|
18.5
|
backbone
of organic molecules
|
Sulfur
|
S
|
0.03
|
0.3
|
component
of most proteins
|
Chlorine
|
Cl
|
0.01
|
0.2
|
major
negative ion in cells
|
Vanadium
|
V
|
0.01
|
Trace
|
--
|
Chromium
|
Cr
|
0.01
|
Trace
|
--
|
Copper
|
Cu
|
0.01
|
Trace
|
many
enzymes
|
Nitrogen
|
N
|
Trace
|
3.3
|
nucleic
acids and proteins
|
Boron
|
B
|
Trace
|
Trace
|
--
|
Cobalt
|
Co
|
Trace
|
Trace
|
--
|
Zinc
|
Zn
|
Trace
|
Trace
|
critical
for some enzymes
|
Selenium
|
Se
|
Trace
|
Trace
|
--
|
Molybdenum
|
Mo
|
Trace
|
Trace
|
critical
for some enzymes
|
Tin
|
Sn
|
Trace
|
Trace
|
--
|
Iodine
|
I |
Trace
|
Trace
|
needed
for thyroid hormone
|
