Elemental Groups of the Crust (based on bonding behavior)
- Lithophile Elements (“Rock-Loving”)
- Tendency: Form ionic bonds with oxygen.
- Examples: O, Si, Ti, Fe, Mn, Al, Mg, Ca, Na, K, and rare earth elements.
- Significance: Major constituents of silicate minerals like quartz and feldspar.
- Chalcophile Elements (“Sulfur-Loving”)
- Tendency: Bond covalently with sulfur (forming sulfides).
- Examples: S, Se, Te, Fe, Ni, Co, Cu, Zn, Pb, Ag, Mo.
- Significance: Essential for ore minerals like pyrite and galena.
- Siderophile Elements (“Iron-Loving”)
- Tendency: Form metallic bonds with iron.
- Examples: Fe, Ni, Co, Ru, Rh, Pd, Ir, Os, Au.
- Significance: Often found in Earth’s core and meteorites.
- Atmosphile Elements (“Gas-Loving”)
- Tendency: Remain in gaseous state in the atmosphere.
- Examples: N, O, He, Ne, Ar, Kr, Xe.
- Significance: Crucial for atmospheric composition and life support.
- Biophile Elements (“Life-Loving”)
- Tendency: Found in living organisms.
- Examples: C, H, O, N, P, S, Ca, Mg, K, Na, Fe, Zn, Cu.
- Significance: Essential for biological molecules (DNA, proteins, enzymes).
Composition of Earth crust (% by weight)
|
Non – metallic |
Oxygen |
O 2- |
46.60% |
74.32% ( 3⁄4th) |
|
Silica |
Si4+ |
27.72% |
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|
Metallic |
Aluminium |
Al3+ |
8.13% |
1⁄4th of the total
|
|
Iron |
Fe2+ |
5.00% |
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|
Calcium |
Ca2+ |
3.63% |
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|
Sodium |
Na+ |
2.83% |
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|
Potassium |
K+ |
2.59% |
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|
Magnesium |
Mg2+ |
2.09% |
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|
Others – 1.41% |
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