Exam 2

Question 1

Electronic Configuration

Completed shells

Ionic bond

Covalent bond

Metallic bond

Van der Waals bond

Hydrogen bond

Answer 1

list the budget of the electrons in each of the shells and subshells

Noble gas electronic configuration

opposite charges attract electron clouds together

incomple outer shell merge

electrons shared freely through lattice

weak interactions

polarized portions of molecule “stick” together

Question 2

Ionization potential

Electron negativity

Coordination number

Answer 2

The amount of energy to deprive an atom of one or more electrons

Tendency of an atom to attract electrons into its outer shell empirical

Is the number of ions or atoms immediately surround an atom or ions of interest

Question 3

Pauling/Goldschmidt 1st Rule

Answer 3

The distance between cation-anion = total radi
Use Rc/Ra to determine the coordination number
Pure metals have Rc/Ra =1 => PCC or HCP
If the center cation become smaller than the XII site, it drops to the next lower coordination number
It will do this even if it is slightly too large for the next lower site
It is easy to fit slightly large cation

Question 4

Pauling/Goldschmidt 2nd Rule

Answer 4

Electronic bond strength = valance/CR (coordination number)
“the electrostatic valance principle”
an ionic structure will be stable to extent that the sum of the strengths of electrostatic bonds that reach an anion from adjacent cations = the charge of that anion

Question 5

Pauling/Goldschmidt 3rd Rule

Answer 5

The sharing of edges, particular of faces, of adjacent polyhedra tends to decrease the stability of an ionic structure

Question 6

Pauling/Goldschmidt 4th Rule

Answer 6

In a crystal with different cations, those of high valance and low coordination number tend not to share polyhedral elements

Question 7

Pauling/Goldschmidt 5th Rule

Answer 7

The number of different kinds of constituents in a crystal tends to be small
Using the analogy of CP oxygens, this rule states that the number of interstitial sites that are filled in a regular and periodic array tends to be small

Question 8

Solid Solution

Substitutional

Couple substitution

Interstitial

Omission

Answer 8

a mineral structure in which specific atomic sites are occupied in variable proportions by 2 or more different chemical elements or groups

One element substitutes for another

2 elements with different charges swap to preserve charge balance

extra atoms added to a structure

atoms omitted from the structure in a regular way

Question 9

Interstitial solid solution

Answer 9

extra atoms added to structure

usually neutrals or occupied with an omission or subtristiution

Question 10

Omission solid asolt

Answer 10

vacant sites in structure

Question 11

Exolution

Answer 11

Homogeneous crystal solid seperate

Question 12

Phase transformation
Polymorphism

Polymorph

Polymorphous or Polymorphic

Answer 12

the transformation of mineral structure in a single composition depending on extrinsic variables

one or group of minerals with a single composition

having the same composition but different structures

Question 13

Purephase

Pseudomorphism

Answer 13

no solid solution

the replacement of 1 mineral by another while retaining characteristic (eg shape, texture) of the 1st mineral

Question 14

Solid solid net transfer reactions

Answer 14

Involve solids only, different composition, material must diffuse from one site to another for reactions to proceed

Question 15

Continuous (multivariate) reactions

Answer 15

Phases change proportions and composition, but do not suddenly appear or disappear

Question 16

Quantitative mineral analysis

Answer 16

when we break down the rock, always oxide presents inside

Question 17

X-Ray Diffraction

Answer 17

important tool to study minerals, coordination, the arrangment and number of ions surrounding a central ion

Question 18

Diffraction

Answer 18

Wavelength of incoming diffracted radiation is near the spacing of the structure being imaged

Question 19

Bragg’s Law

Answer 19

lamda = 2d sin theta

Question 20

Precession picture

Answer 20

Each point is a single plane (111), shows symmetry, internsities give positions of atoms in the unit cell, used to calculate positions of atoms in structure, including very complex proteins (e.g DNA)

Question 21

Power diffractometer

Answer 21

Finely ground sample
Crystals in random orientations (often moving)
X-ray beam interacts with many crystals
All possible reflection are recorded
Simple and powerful technique for geolgy
Film image to determine d for many (hkl) planes at once

Question 22

Defractogram

Answer 22

define X-Ray structure, crystal composition
Mixtures of minerals
Reflections are not always perfectly reproduced
Instrument noises
Multiple minerals
Detective work
XRD Patterns of the soils