Introduction to Mineralogy Dr. Tark Hamilton Chapter 3: Lecture 7 The 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 # 92 U 1s < 1 H 1s –Electrons in same shell repel each other 9 F > 3 Li –Heavier atoms/ions are bigger down groups 56 Ba > 12 Mg +/- charges of nearest neighbours count – Al +3 is smaller in (AlO 4 ) -5 than with (AlO 6 ) -9

Ice - Covalent Bonded Mineral & Rock: H 2 O 1 Angstrom Strong molecular bonds within waters 1.8 Angstrom Weak Hydrogen bonds between waters Open Channels (low density) Each Oxygen is Tetrahedrally coordinated by 4 Hydrogens H-O-H bond angle 104.5° (Tetrahedral = 109.5° High O Low O There are many Higher Pressure Polymorphs!

Sub-Atomic Physics for Dummies & Mineralogists

The Bohr Hydrogen Atom Explains H emission lines Classical orbits decay Better than Rutherford’s Plum Pudding Model

Elements & Isotopes Carbon Atomic # 6 At.wt Nitrogen Atomic # 7 At.wt Oxygen Atomic # 8 At. wt 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)

Electrons Locations as Schroedinger’s Wave Functions S Orbital S Orbital Radius

Subshell Orbital Geometries S1,2,3 Orbitals P2 x y z Orbitals D3 Orbitals

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 for X-ray generation & identification s, p, d, f – Electron energy levels orbital shapes & directions Every electron in every element has a unique set of quantum numbers & an energy level all its own. Electron jumps = Δ energy, photons

Quantum Numbers = Electron E’s

Magnetic Spin Quantum # Stern-Gerlach Experiment Spin +/- ½ Magnetic Field & Induction Deflected Ag beam by strong Magnetic field Gave 2 spots Half filled 5s 1

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 m l – magnetic, direction/orientation of orbital Spin Quantum Number (empirical) m s – spin magnetic Pairs of electrons in subshells: s, p, d, f differ in the sign of their spin magnetic #

Elements and Ions Low Ionization potential forms Ions easily Lone electrons ionize easily Noble gases need X-rays to ionize Electronegativity attracts electrons to atom in covalent bonds Geeze-Louise! This looks like the list of major & minor elements!