GEO Lecture 11

Chemical Bonding 

• Describes how atoms attach with each other to form molecules 

• Valence electrons (in the outer electron shell) are involved in chemical bonding atoms tend to gain or lose electrons until the valence shell is full 

Mineral formation 

• Minerals form when atoms bond in a crystalline arrangement 

• Can occur via precipitation from a solution 

• As magma is emplaced at depth or extruded onto the surface, it starts to cool

• Minerals form by crystallization from cooling magma

• Biological precipitation by the action of organisms

Silicate Minerals 

• Largest group of minerals on earth (make up ~90% of earth's crust 

• Built around the silicon oxygen tetrahedron, an ion with a charge of -4 and formula si04, that forms bonds with positively charged metal ions 

Non-silicate Minerals 

• Crystal structure does not include the silica-oxygen tetrahedron 

• Ex: gold, silver, copper, apatite, etc

Important terms

• ore= a rock or sediment containing valuable minerals extracted from the earth through mining 

• grade= concentration of the desired material contained in the ore

• Alloy= a mixture of elements in which at least one is a metal 

• smelting= applying heat to an ore to extract a metal 

Mineral resources 

• Minerals are nonrenewable resources- rate of use is greater than rate of regeneration 

• Ore minerals occur with less desirable components called gangue that must be separated 

• Metals form bonds with other elements so energy is required to separate the metal from the mineral 

• Mining, concentrating, smelting, and refining are extremely energy intensive processes

• Silicate minerals are not usually metal ores because the energy required to separate metals is too high 

• Difference between fossil fuels and mineral deposits is that mineral deposits are inorganic, and fossil fuels are organic 

Si production 

• Metalloid-some metal properties 

• Obtained from quartz-widely available 

• Large energy required to split si and o bonds 

• Sio2 redacted in electric arc furnace with wood, charcoal or coal 

Abundant metals 

• Occur at greater than 01% concentration on average in earth's crust