Lesson 3: Crystal Chemistry

Question 1

Mechanical Properties

___________lithosphere, __________ asthenosphere, _____________mantle or mesosphere, __________outer core, and __________inner core.

Answer 1

strong, weaker, lower, liquid, solid

Question 2

Compositional Layers of the Earth

Answer 2

• Continental Crust
• Oceanic Crust
• Mantle
• Core

Question 3

Mechanical Layers of the Earth

Answer 3

• Lithosphere
• Asthenosphere
• Mesosphere
• Outer Core
• Inner Core

Question 4

• 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.

Answer 4

Mantle

Question 5

• Consists primarily of iron (~85%) with significant amounts of nickel (~5%).
• Other lighter elements such as oxygen, sulfur, and hydrogen make up ~8–10%.

Answer 5

Core

Question 6

Between the upper and lower crust.

Answer 6

Conrad Discontinuity

Question 7

Between the crust and mantle.

Answer 7

Mohorovičić Discontinuity (Moho)

Question 8

Between the outer mantle and inner mantle.

Answer 8

Repetti Discontinuity

Question 9

Between the mantle and core.

Answer 9

Gutenberg Discontinuity

Question 10

Between the outer core and inner core.

Answer 10

Lehmann Discontinuity

Question 11

8 Most Common Elements in the Earth’s Crust

Answer 11

• O
• Si
• Al
• Fe
• Ca
• Na
• K
• Mg

Question 12

The Earth consists almost entirely of _______compounds

Answer 12

Oxygen

Question 13

Oxygen constitutes ______% of the total volume of the crust.

Answer 13

94

Question 14

The smallest subdivision of matter that retains the characteristics of an element.

Answer 14

Atom

Question 15

A subatomic particle with a positive electrical charge.

Answer 15

Proton

Question 16

A subatomic particle with a -1 elementary electric charge.

Answer 16

Electron

Question 17

Consists of electrically positive protons and electrically neutral neutrons.

Answer 17

Nucleus

Question 18

An orbit followed by electrons around the nucleus.

Answer 18

Shell

Question 19

Represents the number of protons in one atom of an element.

Answer 19

Atomic Number

Question 20

Atoms of the same element but with different numbers of neutrons.

Answer 20

Isotope

Question 21

• 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.

Answer 21

Bohr’s Model

Question 22

• 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.

Answer 22

Schrodinger’s Model

Question 23

• 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.

Answer 23

Bonding Forces in Crystals

Question 24

Types of bonds found in minerals

Answer 24

• Ionic Bond
• Covalent Bond
• Metallic Bond
• Van der Waals Bond
• Hydrogen Bond

Question 25

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).

Answer 25

Ionic Bond

Question 26

– "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.

Answer 26

Covalent Bond

Question 27

- 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.

Answer 27

Metallic Bond

Question 28

- Weakest of the chemical bonds. Residual bonding. - Arises from the interactions between uncharged atoms/molecules.

Answer 28

Van der Waals Bond

Question 29

A molecule created from two identical simpler units.

Answer 29

Dimer

Question 30

- 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.

Answer 30

Hydrogen Bond