Lecture 2 (9/11/2006) – Crystal Chemistry Part 1: Atoms, Elements, and Ions.
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Transcript of Lecture 2 (9/11/2006) – Crystal Chemistry Part 1: Atoms, Elements, and Ions.
Lecture 2 (9/11/2006) – Lecture 2 (9/11/2006) –
Crystal ChemistryCrystal Chemistry
Part 1: Part 1:
Atoms, Elements, and Atoms, Elements, and IonsIons
Mineralogy WebsiteMineralogy Website
www.d.umn.edu/~mille066/Teaching/www.d.umn.edu/~mille066/Teaching/Mineralogy06.htmMineralogy06.htm
What is Crystal Chemistry?What is Crystal Chemistry?
study of the atomic structure, physical study of the atomic structure, physical properties, and chemical composition of properties, and chemical composition of crystalline material crystalline material
basically inorganic chemistry of solidsbasically inorganic chemistry of solids the structure and chemical properties of the the structure and chemical properties of the
atom and elements are at the core of crystal atom and elements are at the core of crystal chemistry chemistry
there are only a handful of elements that there are only a handful of elements that make up most of the rock-forming minerals make up most of the rock-forming minerals of the earthof the earth
Fe – 86%Fe – 86%S – 10%S – 10%Ni – 4%Ni – 4%
Chemical Layers of the EarthChemical Layers of the Earth
SiO2 – 45%SiO2 – 45%MgO – 37%MgO – 37%FeO – 8%FeO – 8%Al2O3 – 4%Al2O3 – 4%CaO – 3% CaO – 3% others – 3%others – 3%
Average composition of the Earth’s Average composition of the Earth’s CrustCrust
(by weight, elements, and volume)(by weight, elements, and volume)
The AtomThe Atom
The Bohr Model The Schrodinger ModelNucleus
- contains most of the weight (mass) of the atom- composed of positively charge particles (protons) and
neutrally charged particles (neutrons)Electron Shell
- insignificant mass- occupies space around the nucleus defining atomic
radius- controls chemical bonding behavior of atoms
Elements and IsotopesElements and Isotopes
Elements are defined by the number of protons in Elements are defined by the number of protons in the nucleus (atomic number). the nucleus (atomic number).
In a stable element (non-ionized), the number of In a stable element (non-ionized), the number of electrons is equal to the number of protonselectrons is equal to the number of protons
Isotopes of a particular element are defined by the Isotopes of a particular element are defined by the total number of neutrons in addition to the number total number of neutrons in addition to the number of protons in the nucleus (isotopic number). of protons in the nucleus (isotopic number).
Various elements can have multiple (2-38) stable Various elements can have multiple (2-38) stable isotopes, some of which are unstable (radioactive)isotopes, some of which are unstable (radioactive)
Isotopes of a particular element have the same Isotopes of a particular element have the same chemical properties, but different masses. chemical properties, but different masses.
Isotopes of Titanium (Z=22)Isotope Half-life Spin Parity Decay Mode(s) or Abundance38Ti 0+ 39Ti 26 ms (3/2+) EC=100, ECP+EC2P ~ 14 40Ti 50 ms 0+ EC+B+=100 41Ti 80 ms 3/2+ EC+B+=100, ECP ~ 100 42Ti 199 ms 0+ EC+B+=100 43Ti 509 ms 7/2- EC+B+=100 44Ti 63 y 0+ EC=100 45Ti 184.8 m 7/2- EC+B+=100 46Ti stable 0+ Abundance=8.0 1 47Ti stable 5/2- Abundance=7.3 1 48Ti stable 0+ Abundance=73.8 1 49Ti stable 7/2- Abundance=5.5 1 50Ti stable 0+ Abundance=5.4 1 51Ti 5.76 m 3/2- B-=100 52Ti 1.7 m 0+ B-=100 53Ti 32.7 s (3/2)- B-=100 54Ti 0+ 55Ti 320 ms (3/2-) B-=100 56Ti 160 ms 0+ B-=100, B-N=0.06 sys 57Ti 180 ms (5/2-) B-=100, B-N=0.04 sys 58Ti 0+ 59Ti (5/2-) B-=? 60Ti 0+ B-=? 61Ti (1/2-) B-=?, B-N=? Source: R.B. Firestone
UC-Berkeley
Properties of ElectronsProperties of Electrons
Occur in discrete (quantized) energy levels or Occur in discrete (quantized) energy levels or orbitals around the nucleusorbitals around the nucleus
Behave as particles with wave-like propertiesBehave as particles with wave-like properties Position of an electron in space around the nucleus is Position of an electron in space around the nucleus is
a probability function defined by 4 quantum numbersa probability function defined by 4 quantum numbersnn – principle quantum number (= 1, 2, 3, 4...) – principle quantum number (= 1, 2, 3, 4...)
defines the energy level of the primary electron shelldefines the energy level of the primary electron shellll – azimuthal quantum number (= – azimuthal quantum number (= n n -1)-1)
defines the type and number of electron subshells (s, p, defines the type and number of electron subshells (s, p, d, f, ...)d, f, ...)mm – magnetic quantum number (= + – magnetic quantum number (= +ll to - to -l l ))
defines orientation and number of orbitals in each defines orientation and number of orbitals in each subshellsubshellss – spin quantum number (= +1/2 or -1/2) – spin quantum number (= +1/2 or -1/2)
defines direction of spin of the electron in each orbitaldefines direction of spin of the electron in each orbital
Structure of the Periodic TableStructure of the Periodic Table# of Electrons in Outermost Shell Noble
Gases
Anions
--------------------Transition Metals------------------
Primary Shell being filled
Ions, Ionization Potential, and Valence Ions, Ionization Potential, and Valence StatesStates
CationsCations – elements prone to give up one or more electrons from – elements prone to give up one or more electrons from their outer shells; typically a metal elementtheir outer shells; typically a metal element
AnionsAnions – elements prone to accept one or more electrons to – elements prone to accept one or more electrons to their outer shells; always a non-metal elementtheir outer shells; always a non-metal element
Ionization PotentialIonization Potential – measure of the energy necessary to strip – measure of the energy necessary to strip an element of its outermost electron an element of its outermost electron
ElectronegativityElectronegativity – measure strength with which a nucleus – measure strength with which a nucleus attracts electrons to its outer shellattracts electrons to its outer shell
Valence StateValence State (or oxidation state) – the common ionic (or oxidation state) – the common ionic configuration(s) of a particular element determined by how configuration(s) of a particular element determined by how many electrons are typically stripped or added to an ionmany electrons are typically stripped or added to an ion
1st Ionization Potential
Electronegativity
Elements with a single outer s orbital electron
Anions
Cations
Valence States of Ions common Valence States of Ions common to Rock-forming Mineralsto Rock-forming Minerals
CationsCations – generally – generally relates to column relates to column in the periodic in the periodic table; most table; most transition metalstransition metals have a +2 have a +2 valence state for valence state for transition metals, transition metals, relates to having relates to having two electrons in two electrons in outer outer
AnionsAnions – relates – relates electrons needed electrons needed to completely fill to completely fill outer shellouter shell
Anionic Groups – Anionic Groups – tightly bound tightly bound ionic complexes ionic complexes with net negative with net negative chargecharge
+1 +2 +3 +4 +5 +6 +7
-2 -1
-----------------Transition Metals---------------