Part 1:bonding In Minerals

Front 1

Mineralogy

Back 1

Study of minerals
, specifically:
composition
structure (= arrangement of atoms)
physical properties
classification
formation, occurrence
stability

Front 2

Petrology

Back 2

Study of rocks
Rocks (most) are composed of
minerals

Front 3

Mineral

Back 3

naturally occurring
homogeneous
solid
has a structured, periodic (3-dimensional) arrangement of atoms (= crystalline)
definite (within a range of) chemical composition
produced by inorganic processes? --- arguable)
ex:ice

Front 4

mineraloid

Back 4

fulfills most of these requirements, especially having definite chemical composition
Example: opal ,water

Front 5

crystalline

Back 5

possesses a 3-dimensional periodic arrangement of atoms

Front 6

Amorphous

Back 6

antonym of crystalline; no periodic arrangement of atoms

-crystalline vs. amorphous: distinguished based on whether substance diffracts X-rays; requires
periodicity over distances of about 20nm.

Front 7

polymorphs

Back 7

minerals that have the same chemical composition but different structure
Examples: diamond and graphite are polymorphs.

Front 8

isomorphs

Back 8

have same structure but different composition
ex: hematite structures- corundum + Ilmenite

Front 9

Compound
Stoichiometry
element
atom

Back 9

stable combination of elements, electrically neutral
-ratio of elements in a mineral
Example: the stoichiometry of quartz is Si and O in a 1:2 ratio (SiO2)
-simplest form of matter;
can’t be separated into different substances by ordinary chemical reactions
-smallest unit of matter that retains the properties of the element

Front 10

atomic number
mass number
isotopes
atomic weight

Back 10

-number of protons in the nucleus; characteristic of the element
-# of protons + # of neutrons in the atom
-elements having same atomic number, but different number of neutrons.
Examples: C12 13 14
-mass of 1 mole of that substance weighted average over the naturally occurring isotopes

Front 11

ion
cation
anion

Back 11

-charged atom or tightly bound molecule
-positively charged
-negatively charged

Front 12

Electronic structure
octet rule

Back 12

-provides an understanding of the ways and proportions that various elements occur in minerals
-oms tend to gain or lose electrons to
gain a filled outer shell;which has eight electrons
for elements below the second row. Stable configuration is for the outer shell to be either
filled or empty - like that of a noble gas

Front 13

General Rules for assigning formal charge

Back 13

alkali metals (first column): always +1 (Na, K, etc.)
alkaline earths (second column): always +2 (Mg, Ca, Sr, Ba)
halogens (column 7): always -1 (F, Cl, etc.)
Column (III): Al, B, etc. are +3
valence for a native element is always 0
Si: +4
C: can be anything from -4 to +4
Fe can be +2 or +3; Mn can be +2 or +4

Front 14

Electronegativity (EN)

Back 14

measure of an atom’s ability to acquire an electron
useful concept for describing types of bonds.
in periodic table:
upper right are most electronegative (O and F) left and lower left have lowest EN (metals)
-difference in electronegativity can
be used to deduce nature of bond

Front 15

Ionic Bond

Back 15

between elements with large EN difference (e.g., between Na and F) complete transfer of electrons from cation to anion
moderately strong bond: brittle, moderately high melting point electrical insulators

Front 16

covalent bond

Back 16

between elements with similar, but high EN
electrons shared between elements
very strong bonds (= short bond distances)brittle; high melting point; Orbital geometry is common: sp2 hybrid =trigonal geometery
sp3 hybrid = tetrahedral geometry
electrical insulators

Front 17

metallic bond:

Back 17

between elements with similar, but low EN (e.g., Cu-Cu)
All valence electrons given up to “conduction band”
cationic metal cores with mobile electrons
moderate melting point excellent electrical and thermal conductivity
opaque; metallic luster

Front 18

van der Waal's bond:

Back 18

between neutrally charged particles polarization of electron distribution very weak bond often occurs between sheets in layered minerals
graphite,

Front 19

hydrogen bond:

Back 19

between H (of hydroxyl, or water), and lone e- pair on adjacent oxygen. weak bond, but important in some minerals (ice, clay minerals, gypsum)