Camosun College GEOS 250 Lectures: 9:30-10:20 M T Th F300 Lab: 9:30-12:20 W F300
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Transcript of Camosun College GEOS 250 Lectures: 9:30-10:20 M T Th F300 Lab: 9:30-12:20 W F300
Introduction to MineralogyDr. Tark Hamilton
Chapter 3: Lecture 7The Chemical Basis of Minerals
(sizes, shapes & directions)
Camosun College GEOS 250
Lectures: 9:30-10:20 M T Th F300
Lab: 9:30-12:20 W F300
Controls of Size in Atoms & Ions
• In lone atoms (few and far between):– Electrons are attracted by Z = Atomic #
• 92U1s < 1H1s
– Electrons in same shell repel each other• 9F > 3Li
– Heavier atoms/ions are bigger down groups• 56Ba > 12Mg
• +/- charges of nearest neighbours count– Al+3 is smaller in (AlO4)-5 than with (AlO6)-9
Ice - Covalent BondedMineral & Rock: H2O
1 AngstromStrong molecular bonds
within waters
1.8 AngstromWeak Hydrogen bonds
between waters
Open Channels(low density)
Each Oxygen isTetrahedrally coordinated
by 4 Hydrogens
H-O-H bond angle104.5°
(Tetrahedral = 109.5°
High OLow O
There are many Higher Pressure Polymorphs!
The Bohr Hydrogen Atom
Explains H emission lines Classical orbits decay
Better thanRutherford’s
Plum PuddingModel
Elements & Isotopes
CarbonAtomic # 6
At.wt. 12.011
NitrogenAtomic # 7
At.wt. 14.0067
OxygenAtomic # 8
At. wt. 15.9994
Stable Isotopes
Geologically Common & Important Elements in Minerals
Major Elements: Al, Ar, Ca, C, H, K, Fe,Mg, Mn, N, Na, O, P, S, Si, Ti
(16)
Minor Elements: As, B, Ba, Be, Bi, Br, Ce,Cd, Cs, Cl, Cr, Co, Cu, F, He, La, Pb, Hg, Mo,Nb, Ni, Ra, Rn, Sc, Se, Sr, Sn, W, V, Y, Zn, Zr
(32)
Trace Elements: Ag, Au, Dy, Eu, Ga, Gd,Hf, Ho, I, Ir, Li, Lu, Nd, Os, Pd, Pt, Rb, Rh,
Sm, Ta, Tb, Te, Tl, Th, Tm(25)
Orbital Quantum Numbers& Order of Filling Sub-shells
Spectral Line Names:
s – Sharp
p – Principal
d – Diffuse
f - Fundamental
Quantum Numbers for Dummies & Mineralogists
n Principal Quantum # = size of atom& row in periodic table
K, L, M: important shells forX-ray generation & identification
s, p, d, f – Electron energy levelsorbital shapes & directions
Every electron in every elementhas a unique set of quantum numbers
& an energy level all its own.
Electron jumps = Δ energy, photons
Magnetic Spin Quantum #Stern-Gerlach Experiment
Spin +/- ½
Magnetic Field & Induction
Deflected Ag beamby strong
Magnetic fieldGave 2 spotsHalf filled 5s1
Pauli Exclusion Principle:No 2 electrons may have identical values
for all quantum numbers
Schroedinger’s Quantum Numbers• n – principal shell (distance from nucleus)• l – azimuthal, shape of orbital• ml – magnetic, direction/orientation of orbital
Spin Quantum Number (empirical)• ms – spin magnetic
• Pairs of electrons in subshells: s, p, d, f differ in the sign of their spin magnetic #