Lesson 3: Crystal Chemistry Flashcards
Mechanical Properties
___________lithosphere, __________ asthenosphere, _____________mantle or mesosphere, __________outer core, and __________inner core.
strong, weaker, lower, liquid, solid
Compositional Layers of the Earth
- Continental Crust
- Oceanic Crust
- Mantle
- Core
Mechanical Layers of the Earth
- Lithosphere
- Asthenosphere
- Mesosphere
- Outer Core
- Inner Core
- Has a thickness of ~2900 km and constitutes ~83% of the Earth’s total volume.
- This layer is rich in MgO (30–40%) and, to a lesser extent, FeO.
- Contains an average of ~40–45% SiO₂ – ultrabasic composition.
- Basic rocks such as eclogite occur in smaller proportions.
Mantle
- Consists primarily of iron (~85%) with significant amounts of nickel (~5%).
- Other lighter elements such as oxygen, sulfur, and hydrogen make up ~8–10%.
Core
Between the upper and lower crust.
Conrad Discontinuity
Between the crust and mantle.
Mohorovičić Discontinuity (Moho)
Between the outer mantle and inner mantle.
Repetti Discontinuity
Between the mantle and core.
Gutenberg Discontinuity
Between the outer core and inner core.
Lehmann Discontinuity
8 Most Common Elements in the Earth’s Crust
- O
- Si
- Al
- Fe
- Ca
- Na
- K
- Mg
The Earth consists almost entirely of _______compounds
Oxygen
Oxygen constitutes ______% of the total volume of the crust.
94
The smallest subdivision of matter that retains the characteristics of an element.
Atom
A subatomic particle with a positive electrical charge.
Proton
A subatomic particle with a -1 elementary electric charge.
Electron
Consists of electrically positive protons and electrically neutral neutrons.
Nucleus
An orbit followed by electrons around the nucleus.
Shell
Represents the number of protons in one atom of an element.
Atomic Number
Atoms of the same element but with different numbers of neutrons.
Isotope
- Developed in 1913 by Danish physicist.
- Due to the specific and characteristic wavelength (λ) values of light emitted by all chemical elements when heated to high temperatures, this scientist concluded that electrons occupy specific energy levels at various distances from the nucleus.
Bohr’s Model
- Proposed the “Quantum-Wave Model.”
- Based on the studies of De Broglie, Bohr, and Sommerfeld.
- Electrons exhibit wave-like properties (undulations of matter).
- To fully specify the position of an electron in three-dimensional space, three quantum numbers are required.
Schrodinger’s Model
- Responsible for the physical and chemical properties of minerals.
- Directly related to hardness, cleavage, fusibility, electrical and thermal conductivity, compressibility, and the coefficient of thermal expansion.
- Stronger average bond results in a harder crystal, higher melting point, and a smaller coefficient of thermal expansion.
Bonding Forces in Crystals
Types of bonds found in minerals
- Ionic Bond
- Covalent Bond
- Metallic Bond
- Van der Waals Bond
- Hydrogen Bond
Achieved when one or more electrons in the valence shell of an atom are transferred to the valence shell of another (both achieve an inert gas configuration).
Ionic Bond
– “Electron-sharing” = strongest of the chemical bonds.
- Minerals have general insolubility, great stability, and very high melting points.
- The number of covalent bonds an atom may form can commonly be predicted by counting the number of electrons required to achieve a stable electron configuration.
- Octet Rule – Atoms are most stable when their valence shells are filled with 8 electrons.
Covalent Bond
- Collective sharing of a sea of valence electrons between several positively charged metal ions.
- Results in metals’ high plasticity, tenacity, ductility, conductivity, and generally low hardness.
- Pure metallic bonding can be observed in native metals.
Metallic Bond
- Weakest of the chemical bonds.
Residual bonding. - Arises from the interactions between uncharged atoms/molecules.
Van der Waals Bond
A molecule created from two identical simpler units.
Dimer
- A special type of dipole-dipole attraction between molecules, not a covalent bond to a hydrogen atom.
- Results from the attractive force between a hydrogen atom covalently bonded to a very electronegative atom (such as N, O, or F) and another very electronegative atom.
- Are present in micas and clay minerals, which contain hydroxyl groups.
Hydrogen Bond
