Earth's Crust and Mantle Quiz

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Questions and Answers

Which elements dominate both the Earth's crust and mantle?

Hydrogen and carbon

Calcium and sodium

Aluminum and iron

Oxygen and silicon (correct)

What is the primary composition of Earth's core?

Calcium and magnesium

Hydrogen and helium

Silicon and aluminum

Iron with nickel (correct)

Which two elements contribute to the composition of most minerals found in igneous and metamorphic rocks?

Aluminum and calcium

Iron and titanium

Sodium and magnesium

Oxygen and silicon (correct)

How does the composition of oceanic crust differ from the continental crust?

Oceanic crust is richer in iron and magnesium. Signup and view all the answers

Which of the following best describes the relationship between magnesium and silicon in the Earth's crust and mantle?

Magnesium is more abundant in the mantle than the crust. Signup and view all the answers

Which elements are considered minor components in the Earth's crust but important in some minerals?

Hydrogen and carbon Signup and view all the answers

Which minerals are typically rich in titanium?

Rutile, titanite, and ilmenite Signup and view all the answers

What accounts for variation in the composition of Earth's outer layers?

Lateral and vertical differences in elemental abundance Signup and view all the answers

What type of diagram is used to represent solid solutions with three end members?

Triangular diagram Signup and view all the answers

Which minerals are the end members of the ternary feldspar diagram?

Anorthite, Albite, Orthoclase Signup and view all the answers

Which statement is true about primary and secondary minerals?

Primary minerals can become secondary in different rocks. Signup and view all the answers

What is the significance of essential minerals in rock classification?

They control rock properties. Signup and view all the answers

Which of the following elements is NOT among the 14 that comprise over 99.7 wt % of Earth's crust?

Lead Signup and view all the answers

What is the most abundant mineral in Earth's crust?

Feldspar Signup and view all the answers

What is the approximate percentage of the Earth's crust that consists of silicate minerals?

92% Signup and view all the answers

Which of the following descriptions fits accessory minerals?

They typically do not affect rock properties. Signup and view all the answers

Which mineral would most likely be classified as an accessory mineral?

Apatite Signup and view all the answers

Which of the following is NOT a common element in Earth’s crust?

Gold Signup and view all the answers

Which element has the highest atomic number listed in the content?

Oganesson Signup and view all the answers

What is the definition of a mole in terms of the number of atoms or molecules?

6.022 × 10^23 Signup and view all the answers

What type of element is included in Group 18 of the Periodic Table?

Noble gases Signup and view all the answers

Which statement about isotopes of oxygen is correct?

17O and 18O are less abundant compared to 16O. Signup and view all the answers

Which group contains alkali metals that can substitute for each other in minerals?

Group 1 Signup and view all the answers

What term is used for the process when two different feldspar components unmixed from each other?

Exsolution Signup and view all the answers

What is the mass number of an element if it has 12 protons and 14 neutrons?

24 Signup and view all the answers

Which of the following elements are classified as transition metals?

Gold and Iron Signup and view all the answers

How are elements generally organized in the Periodic Table?

By increasing atomic number Signup and view all the answers

What is the atomic number of a neutral iron atom?

26 Signup and view all the answers

What element is considered a special element and categorized differently from others?

Hydrogen Signup and view all the answers

Which elements are typically classified as the lanthanides?

Elements in the bottom rows designed with asterisks Signup and view all the answers

What occurs to the atomic structure as the atomic number increases?

The number of electrons increases. Signup and view all the answers

Which of the following pairs are correctly categorized under alkaline earth metals?

Ca and Mg Signup and view all the answers

What is the atomic weight of quartz, SiO2?

60.0843 grams/mole Signup and view all the answers

What determines the abundance of different isotopes in nature?

The naturally occurring isotopes' relative frequencies Signup and view all the answers

Which of the following elements is mentioned as a common contributor to radioactivity in minerals?

Uranium Signup and view all the answers

How do you calculate the density of quartz?

Molar weight ÷ molar volume Signup and view all the answers

What is the maximum number of electrons that can occupy a p subshell?

6 Signup and view all the answers

What is the significance of isotopic variations in minerals for geochemists?

They can indicate the genesis of particular minerals or rocks. Signup and view all the answers

How many protons are present in a neutral sodium atom?

11 Signup and view all the answers

What does the symbol 'Z' represent in the unit cell calculation formula?

The number of SiO2 molecules per unit cell Signup and view all the answers

What type of electrons are involved in chemical bonding?

Valence electrons Signup and view all the answers

Which of the following subshells has the highest energy?

5f Signup and view all the answers

What is the charge of a monovalent anion?

-1 Signup and view all the answers

What is the approximate atomic weight of oxygen?

15.999 Signup and view all the answers

How many electrons are in the outer shell of a neutral oxygen atom?

6 Signup and view all the answers

How many molecules of SiO2 are contained in a mole of quartz?

6.022 × 10^23 Signup and view all the answers

What type of radiation is emitted by radioactive minerals?

Alpha and beta particles Signup and view all the answers

Which of the following groups typically forms cations?

Group 1 Signup and view all the answers

What happens when an atom becomes an anion?

It gains electrons. Signup and view all the answers

Which of the following correctly describes a characteristic of atomic masses?

Atomic masses are dimensionless numbers calculated relative to carbon. Signup and view all the answers

Which of the following describes the relationship between cations and anions in ionic bonds?

Cations attract anions. Signup and view all the answers

What are the orbitals with the highest maximum number of electrons?

4f and 5f Signup and view all the answers

What kind of bonding is primarily found in most nonmetallic minerals?

Ionic bonds Signup and view all the answers

Which periods of the periodic table mainly contain elements with valence electrons in s and p orbitals?

Second and third Signup and view all the answers

In terms of energy, how are electrons arranged in an atom?

They fill the lowest energy orbitals first. Signup and view all the answers

What is the typical charge of oxygen when it forms an anion?

-2 Signup and view all the answers

Which property is typically associated with metallic bonds in minerals?

High electrical conductivity Signup and view all the answers

What is the result when sodium and chlorine react chemically?

NaCl is produced Signup and view all the answers

What is a defining characteristic of minerals with covalent bonds?

Very low solubility in water Signup and view all the answers

Which type of elements are described as metallic and more likely to lose electrons?

Metals Signup and view all the answers

Which mineral is an example of a covalent bond?

Diamond (C) Signup and view all the answers

Which mineral contains both Fe2+ and Fe3+ ions?

Magnetite Signup and view all the answers

What is the typical ionic charge of elements in Group 2?

+2 Signup and view all the answers

Which of the following represents the process of an atom losing electrons?

Oxidation Signup and view all the answers

What type of bond is primarily involved in the formation of minerals like quartz (SiO2)?

Covalent bond Signup and view all the answers

What type of element control mineral composition prominently?

Major elements Signup and view all the answers

Transition metals typically show which characteristic regarding ionization?

Unpredictable ionization states Signup and view all the answers

Which of the following minerals is considered to have limited compositional variation?

Fluorite (CaF2) Signup and view all the answers

Which of the following ions cannot combine with Ca2+ to form a mineral?

(NO3)- Signup and view all the answers

In which orbitals are the valence electrons located for elements in the sixth and seventh periods?

s and p orbitals, and d or f orbitals Signup and view all the answers

How many electrons do two oxygen atoms share to form O2 gas?

Four Signup and view all the answers

What type of analysis do mineralogists prefer when determining mineral composition?

Oxide weight % Signup and view all the answers

Which type of mineral typically exhibits high hardness due to covalent bonding?

Diamond Signup and view all the answers

What happens when iron is oxidized to Fe3+?

It easily combines with oxygen to form hematite Signup and view all the answers

What is a common characteristic of molecular ions in minerals?

They function like individual anionic units Signup and view all the answers

What is an example of a metallic mineral?

Copper (Cu) Signup and view all the answers

Which of the following is a divalent cation commonly found in the Earth's crust?

Fe2+ Signup and view all the answers

In olivine analyses, which elements are considered major elements?

Si, Fe, Mg Signup and view all the answers

What type of bond is present in diatomic gases such as N2?

Complete covalent bond Signup and view all the answers

Which type of bond is characterized by the ability to conduct heat well?

Metallic bonds Signup and view all the answers

What anionic group is a key feature in the mineral calcite?

(CO3)2- Signup and view all the answers

Which property is associated with minerals that have ionic bonds regarding their ability to break?

Brittle with good cleavage Signup and view all the answers

What process occurs when iron atoms become oxidized?

They lose electrons Signup and view all the answers

Which type of bonds typically have low crystal symmetry?

Covalent bonds Signup and view all the answers

What is the effect of trace elements in mineral compositions?

Provide key formation information Signup and view all the answers

How do anionic groups, such as (SiO4)4-, behave in minerals?

They act as polyatomic ions Signup and view all the answers

What type of bond occurs when two atoms share electrons to achieve stability?

Covalent Signup and view all the answers

Which mineral is characterized by the formula CaSO4?

Anhydrite Signup and view all the answers

What type of bond is formed when two chlorine atoms bond covalently?

Covalent Bond Signup and view all the answers

Which statement accurately describes the difference between ionic and covalent bonds?

Ionic bonds generally have weak bonds compared to covalent bonds. Signup and view all the answers

In what way do metallic bonds differ from covalent and ionic bonds?

Metallic bonds involve electron sharing among many atoms. Signup and view all the answers

What is the primary characteristic of van der Waals bonds?

They arise from weak electrostatic forces. Signup and view all the answers

What is a defining feature of minerals with ionic bonding?

They have significantly high melting points. Signup and view all the answers

Which mineral is an example of a substance that exhibits predominantly metallic bonding?

Cu Signup and view all the answers

How does the character of silicon-oxygen bonds in minerals like quartz differ from pure covalent bonding?

They involve some level of ionic character. Signup and view all the answers

What is the typical bond character in silicates?

50% ionic and 50% covalent Signup and view all the answers

Which type of bonding is NOT typically associated with the mineral graphite?

Ionic Bonding Signup and view all the answers

What type of bonds exist in the mineral brucite?

Combinations of hydrogen and ionic bonds Signup and view all the answers

What aspect of metal minerals like pyrite and stibnite generally combines with covalent bonding?

Low ionic character Signup and view all the answers

What happens to the solubility of ionic crystals when placed in water?

They tend to dissolve easily because of weak bonds. Signup and view all the answers

Which bond type is generally stronger than the others?

Covalent Bonds Signup and view all the answers

How do the properties of minerals correlate with their bond types?

Bond types significantly influence the hardness and melting points of minerals. Signup and view all the answers

What is the ideal stoichiometry for olivine?

(R)2SiO4 Signup and view all the answers

Which elements are typically found in significant amounts in olivine?

Fe, Mg, Mn Signup and view all the answers

What are the primary end members of olivine?

Forsterite, Fayalite Signup and view all the answers

What is the purpose of normalization in mineral analysis?

To express elemental compositions in terms of atom numbers Signup and view all the answers

Which minerals are noted for having complex substitution patterns compared to olivine?

Garnets Signup and view all the answers

How are the percent values of forsterite and fayalite calculated in olivines?

Fe/(Mg+Fe) Signup and view all the answers

Which olivine sample has nearly 100% forsterite content?

Burma Signup and view all the answers

What is a common analytical error affecting olivine stoichiometry?

Inclusions of other minerals Signup and view all the answers

What is the role of Excel programs in mineral analysis?

They help in the normalization process. Signup and view all the answers

What describes the substitution capabilities of Ca in olivine?

Ca is limited in its substitution compared to Mg and Fe Signup and view all the answers

What is the significance of the formula (Ca,Na,K)(Al,Si)4O8 for feldspar?

It represents its ideal stoichiometry. Signup and view all the answers

Which method is used to express the normalization of a feldspar formula?

Using percentages to calculate atom numbers Signup and view all the answers

What is the mole fraction of albite in the Grorud feldspar sample?

0.617 Signup and view all the answers

What element is not commonly included in the composition of olivine under typical circumstances?

Ni Signup and view all the answers

Study Notes

Elements and Minerals

Matter composed of atoms of individual elements
Milky Way and Sun primarily hydrogen and helium
Earth's dominant elements (8-10 accounting for most mass) different from celestial bodies
Crust and mantle share major elements, but proportions differ
Core primarily iron, with nickel and other elements
Most geological materials originate from crust or upper mantle

Elements in Crust and Mantle

Oxygen and silicon dominant elements, comprising ~3/4 of crust & ~2/3 of mantle
Other abundant elements: aluminum, iron, calcium, sodium, potassium, and magnesium
Mantle contains more magnesium and iron, less silicon compared to the crust
Hydrogen and carbon minor elements in crust but vital in certain minerals
Rare elements sometimes concentrated to form exotic minerals
Lateral and vertical compositional variations exist (e.g., oceanic vs. continental crust)

Elements and the Periodic Table

Periodic Table orders elements by atomic number (number of protons) correlating to atomic weight and size.
Hydrogen (atomic number 1), Oganesson (atomic number 118)
Elements in numbered periods (rows) and groups (columns) based on electron orbital configuration
About 90 elements occur naturally, the rest artificial (synthesized)
Basic structure similar to Mendeleyev's initial version of 1870, later rearranged to better reflect electron orbital occupancy
Chemists classify elements based on similar properties (different colors on the table) into categories like alkali metals, alkaline earth metals, transition metals, halogens, noble gases, nonmetals (or other metals depending on version), lanthanides, actinides
Scandium and Yttrium sometimes classified with lanthanides
Similar properties among elements in the same groups

Perthite (Exsolved Alkali Feldspar)

Alkali feldspars (Na-feldspar and K-feldspar) commonly substitute each other in minerals
Exsolution—separation of different components upon cooling, resulting in perthite (thin veins of K-feldspar in Na-feldspar)

Atomic Number and Mass

Atomic number (Z) represents the number of protons in an element's nucleus
Also indicates the number of electrons in a neutral atom
Larger Z means larger atomic size, due to increased electron cloud size
Mass number (A) is the total protons and neutrons
Elements have several different isotopes, some more abundant than others

Isotopes of Oxygen

Oxygen consists of three isotopes: 16O, 17O, and 18O
16O is the most common (99.8%)

Moles

Mole defined as 6.022 x 10²³ atoms/molecules (Avogadro's Number)
Standardized atomic mass based on ¹²C (one mole = 12 grams)
Atomic masses (weights) are dimensionless numbers (relating to one mole of carbon)
Atomic weight sum of naturally occurring isotopes, weighted by abundance

Radioactive Minerals

Some isotopes are unstable and undergo radioactive decay (emitting alpha, beta, or gamma radiation)
Minerals are radioactive if they contain radioisotopes
Examples: Torbernite, autunite, and uraninite

Electron Orbitals

Electrons occupy orbitals of increasing energy around the nucleus
S, P, D, and F subshells have specific maximum electron capacities
Orbital shape (e.g., spherical, dumbbell-shaped) relevant for mineral properties (e.g. color)

Ions

Atoms become unstable if valence electron shells incompletely filled
Commonly form ions (cations or anions) for stability
Cations (+ charge) lose electrons; Anions (- charge) gain electrons
Monovalent (charge ±1), divalent (±2), trivalent (±3), tetravalent (±4)

Bonding in Minerals

Ionic Bonds: Attraction between oppositely charged ions (cations and anions)
Example: Halite (NaCl) formation
Oxidation (loss of electrons) and reduction (gain of electrons) involved
Iron oxides (hematite, wüstite, magnetite) variations involve different oxidation states of iron
Bonds in different minerals vary from purely ionic to partially covalent
Covalent Bonds: Sharing of electron pairs between atoms
Example: Hydrogen gas, Oxygen gas, Quartz
Bonds are not totally ionic or covalent, are a spectrum
Metallic Bonds: Many atoms share valence electrons (delocalized electrons)
Example: Gold, silver, copper
Good conductors of heat and electricity
Malleable (ability to be hammered into sheets)
Other Bonds: Van der Waals and hydrogen bonds (weak electrostatic forces)

Solid Solutions

Some minerals are solid solutions; combinations of different elements or minerals intimately bonded
Examples: Plagioclase (CaAl2Si2O8 and NaAlSi3O8), Olivine ((Fe, Mg, Mn, Ca)2SiO4); end-member compositions describe ideal components

Classification of Minerals

Primary (formed during rock formation) vs Secondary (formed later via reactions)
Essential (implied by rock type) vs Accessory (minor presence, not affecting composition)
Examples of essential and accessory minerals (e.g. quartz, zircon, apatite).
Compositional variation (major, minor, and trace elements) in minerals
Abundant elements determining the abundance of various minerals

Chemical Analysis

Methods for determining mineral composition
Example of feldspar analysis using normalization (converting weight percentages to mole percentages to calculate mineral formula)
Useful for understanding the relationship between minerals and rock type

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Description

Test your knowledge on the elements that dominate the Earth's crust and mantle, as well as the core's primary composition. This quiz covers mineral compositions found in igneous and metamorphic rocks and examines the differences between oceanic and continental crusts. Discover the relationships between key elements like magnesium and silicon.