Post on 24-Feb-2016
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Lecture 4
And some rin uphill and down dale,Knapping the chucky stones to pieces wi’ hammers,
Like sae mony roadmakers run daft –They say it is to see how the warld was made.
- Sir Walter Raleigh
Minerals
Webpage for course (daytime)
Webpage for course (nighttime)
Something from the ancient Greek philosopher-scientists
What is a mineral?
A naturally occurring inorganic solid made up of an ordered arrangement of
ATOMS
Difference between minerals and rocks
Atoms, three basic parts
Protons
Neutrons
Electrons
Mass(wt.)
charge
nucleus
electron cloud
Fig. 2.5
Atomic number =
Atomic mass number =
Atomic number = number of protonsAtomic mass number =
number protons and neutrons
Example: Carbon (symbol “C”)atomic number = atomic mass number =
Therefore,6 protons, 6 (12-6) neutrons
Periodic Table
A balanced atom has as many electrons as protons
Electrons are not randomly located
Occur in “shells”
electrons fill shells in a sequential order
1st shell holds up to 2 electrons2nd shell holds up to 8 electrons3rd shell holds up to 8 electrons
Two rules in Nature:
1. electrons occupy shells in a specific order (inner before outer shells)
2. Outer shell that has electrons in it must be full of electrons
Two rules in Nature:1. electrons occupy shells in a specific order
(inner before outer shells)2. Outer shell that has electrons in it
must be full of electrons
Let us develop some characters
Our cast of characters
Our cast of characters
outerelement sym + +/- - # wt. sh. Needs
Hydrogen H
Helium He
Carbon C
Oxygen O
Sodium Na
Chlorine Cl
Iron Fe
Uranium U
So let us meet a hydrogen atom after the Big Bang…
When Harry met Sally
Sodium Chlorine
More formulae
CaCO3 (calcite)KAl2(Si3Al)O10(OH)2 (muscovite)Ca3Al2Si3O12 (garnet)
Silicate minerals
SiO4 tetrahedra
Isolated Olivine
Chains Hornblend
Sheets Mica
Framework Feldspar & Quartz
So, what the atoms are and how to go together determines the characteristics of the mineral:
crystal shapehardnesscleavagechemical propertiesetc. etc.
Graphite and Diamond