Mineral Chemistry Flashcards
0
Q
Describe Elements/Atoms
A
Elements are the basic building blocks of minerals and all life. They are the smallest particles of matter and cannot be broken down by any physical or chemical process. 118 are known to us, 90 of which are naturally occurring. An atom will retain all the characteristics of the elements that make it.
1
Q
Define a rock.
A
A rock is a naturally occurring solid mass composed of various minerals.
2
Q
Describe the structure of an atom.
A
Atoms have a central region called the nucleus that is made up of protons and neurons. Electrons surround the nucleus in energy levels called shells.
3
Q
Where do minerals come from?
A
The Earth’s crust and oceans.
4
Q
List some examples of every day objects that use minerals.
A
Dentist Drill Bits are covered with diamonds, Silicon in Computer Chips are made of quartz
5
Q
Minerals are usually inorganic, what is an exception to this?
A
When mineral formations are mediated by biological processes.
6
Q
Rocks are almost always made up of multiples minerals, what is an example of an exception?
A
Limestone, which is composed of impure masses of calcite.
7
Q
What are rocks made of obsidian and pumice?
A
They are volcanic rocks that are made up of non mineral materials.
8
Q
What is coal?
A
Coal is made of organic matter.
9
Q
How many minerals are on earth?
A
Approximately 4660, each with it’s own unique chemical composition and internal structure.
10
Q
What is the chemical composition of a mineral made of.
A
Elements.
11
Q
List a couple examples of minerals that are made exclusively of one element.
A
Gold and Sulfur.
12
Q
How many elements are minerals usually composed of.
A
Two or more, however being made of a single element is possible.
13
Q
How are protons and neutrons similar?
A
They are approximately equal in size and density.
14
Q
Why are protons and neutrons significant?
A
Together they make up the majority of an atoms mass.
15
Q
Describe electrons.
A
They are negatively charged particles that rapidly orbit the nucleus.
16
Q
Describe protons.
A
Protons are found in the nucleus of an atom and each have a single positive charge.
17
Q
Describe neutrons.
A
Neutrons are found in the nucleus of an atom and have no charge. They occupy spherical energy levels around the nucleus.
18
Q
How are electrons different from both neutrons and protons?
A
Electrons are smaller and lighter than both neutrons and protons.
19
Q
What differentiates each atom from one another?
A
There are atoms of every element, each having a certain number of protons.
20
Q
What is another name for the number of protons in an atom?
A
Atomic Number
21
Q
What is the Atomic Weight of an atom?
A
Atomic Weight is approximately the total number of Protons and Neutrons in the atom’s nucleus. Each single particle accounts for one unit of mass.
22
Q
Do electrons have any mass?
A
An electron has 0.05% of the mass of a proton.
23
Q
What is the significance of the Atomic Number?
A
Elements are cataloged by atomic number.
24
What element has the highest Atomic Number of the naturally occurring elements?
Uranium. It's atomic number is 92.
25
How many electrons are there usually in an atom?
In any given atom, the number of electrons will equal the number of protons, or Atomic Number.
26
Why are the number of electrons and protons equal in an atom?
This creates an electrically neutral state for the atom as a whole. The positively charged particles 'cancel out' the negatively charged particles.
27
How do you figure out the number of neutrons in an atom?
Atomic Weight - Atomic Number = # of Neutrons
28
How many particles of electrons can exist in the innermost shell of an atom?
2
29
With the exception of the innermost shell, how many particles of electrons can exist on the shells surrounding the atom?
8
30
What is the most stable configuration for an atom?
An atom is at it's most stable when the number of electrons on it's outermost shell is 8.
31
What are noble gases?
Noble gases are atoms that have 8 particle-s of electrons in their outtermost shell in it's naturally occurring state.
32
How do atoms with less than 8 particles of electrons on their outtermost shell achieve stability?
These atoms will bond with other atoms to achieve a stable configuration.
33
What are the electrons on the outtermost shells of an atom called?
Valence Electrons
34
What happens when atoms bond with one another.
The create an entirely new substance called a compound.
35
What is the attractive force that links atoms together called?
A Chemical Bond
36
Since minerals are made of more than one atom, even if it is the same element, what is it considered?
A compound.
37
What is an ionic bond?
An ionic bond is when one or more electrons are transferred from an atom of a metal element to an atom of a nonmetal element. This atom gives up some of it's electrons, while another receives them.
38
What are atoms that have too many or too few electrons called?
Ions
39
Describe what happens to an atom when ionic bonds occur.
The atom that gives up one or more electrons will become positively charged. By losing the electron, it is losing the neutral charge it had when it's protons and electrons were equal in number. There are more protons (positive charges) than electrons. Similarly, when an atom receives an electron, it becomes negatively charged as it has more electrons than protons.
40
What happens to atoms that have an equal negative charge to another atom's positive charge. (ex, 2+, 2-)
They attract.
41
Why does ionic bonding occur?
To create a compound with overall electrical neutrality between oppositely charged ions.
42
Are compounds any different than the elements that created it?
Yes, compounds will have significantly different properties from their parent elements.
43
How are rocks and minerals different from elements and compounds?
Unlike compounds and elements, the minerals that make up a rock all retain their own separate properties and identities.
44
What are covalent bonds?
A chemical bonding of two nonmetal elements that involves sharing their valence electrons instead of giving or receiving them.
45
Are covalent bonds, or ionic bonds stronger?
Covalent bonds.
46
How does the bonding of elements apply to a mineral?
Minerals are composed of an ordered array of atoms that have chemically bonded to form a particular crystalline structure. The arrangement of the atoms is reflected in the shapes we call crystals.
47
When looking at minerals that that are formed through ions, how is the internal atomic arrangement determined?
By the charges of the ions, and the size of the ions involved.
48
What is it called when compounds made of the same elements bond in different ways?
Polymorphs.
49
What happens to minerals that have the same elements that join in different geometric arrangements?
They form entirely different minerals. For example, Diamond and Graphite both consist entirely of carbon, but are drastically different.
50
What is the difference between Diamond and Graphite.
Diamond is the hardest known gem, and is formed at depths approaching 200km, and is produced by extreme pressures. Where as Graphite is produced under low pressure and temperature and is made of sheets of carbon atoms that are widely spaced and weakly held together. It is so soft, it rubs off on paper.
51
How are Synthetic Diamonds created?
By heating Graphite under high pressure. It is generally lower quality however.
52
Can a pre existing mineral change to another polymorph?
Yes, this can occur with changes of temperature and pressure occur in the surrounding environment.
53
What is important about mineral properties?
The different mineral properties that each mineral exhibits are used when identifying minerals.
54
What is Crystal Habit?
The external expression of a mineral that reflects the orderly internal arrangement. The naturally occurring shape of a mineral.
55
How does the 'traditional' individual crystal look of a mineral occur?
When a mineral has plenty of room and can form without space restrictions. These individual crystals will have distinctive crystal faces.
56
Is Crystal Habit always easy to identify?
No, when the growth of an individual crystal is interrupted by competition of space, the mineral will become an intergrown mass of crystals.
57
Is Crystal Habit a reliable way to identify minerals.
No
58
What is Lustre?
The appearance or quality of light reflected from the surface of a mineral crystal.
59
What are the different types of lustre?
Metallic lustre (a shiny, metallic surface), and nonmetallic lustre (a shiny, glassy, pearly, silky, or earthy surface).
60
What are minerals that appear somewhat metallic in lustre called?
Submetallic
61
When looking at the properties of a mineral, why is colour not always diagnostic?
Because many minerals can have impurities that will alter the colour of the mineral. For example, quartz is colourless, however it can look purple (amethyst), pink (rose quartz), yellowish orange (citrine) or dark brown (smoky quartz)
62
What is the Streak of a mineral?
Streak is the colour of a mineral in it's powdered form. Streak will almost always been similar or the same as the mineral colour.
63
How to you get a mineral's streak?
By rubbing a mineral across a streak plate.
64
What is Hardness?
A mineral's resistance to abrasion or scratching.
65
How do you figure out the Hardness of a Mineral?
By rubbing a mineral of unknown hardness against a mineral of known hardness and comparing.
66
List Mohs Scale of Relative Hardness
10 (hardest) Diamond, 9 Corundum, 8 Topaz, 7 Quartz, 6,5 Streak Plate, 6 Potassium Feldspar, 5.5 Glass and Knife blade, 5 Apatite, 4.5 Wire Nail, 4 Fluorite, 3 Calcite and Copper Penny, 2.5 Fingernail, 2 Gypsum, 1 (softest) Talc
67
What is the Cleavage of a Mineral?
The cleavage of a mineral is it's tendency to break along planes of weak bonding. Cleavage can be identified as the distinctive smooth surfaces produced when a mineral is broken.
68
What is the simplest type of Cleavage?
One plane of Cleavage. This occurs in minerals like mica that have weak bonds in one planar direction. They cleave to form thin flat sheets.
69
How is a mineral's cleavage described when it breaks evenly in multiple directions?
These mineral's cleavage is described by the number of planes exhibited and the angles at which they meet.
70
How is Cleavage different from Crystal Habit?
Crystal Habit is how a mineral can form naturally, however, when broken, it's Cleavage will not resemble the mineral's Crystal Habit.
71
Why might a mineral not have a Cleavage?
When a mineral has chemical bonds of similar strength in all directions. These minerals lack the ability to cleave along certain planes.
72
What is the Fracture of a mineral?
When a mineral without a cleavage is unable to break along a specific plane, it make still fracture in a distinctive manner.
73
How does Quartz behave when broken?
It fractures into a smooth curved surface like broken glass called Conchoidal Fracture.
74
What are some examples of how some minerals fracture.
Into splinters of fibres. However most minerals fracture irregularly and are uneven.
75
How is the Specific Gravity of a Mineral found?
The weight of a mineral is compared to the weight of an equal volume of water. The mineral is measured by how many times more the mineral weighs than the equal volume of water.
76
What are some ways to identify a mineral that won't apply to all minerals?
Taste, smell, the elasticity of a mineral (if it can be bent without breaking and it snaps back), if it's magnetic, touch (ex, soapy, greasy), and even how it reacts to acid or when burned.
77
What is a minerals opacity?
This is how transparent a mineral is. Some minerals are clear and text can be read through them. Some minerals will make the letters appear twice, this is called double refraction. Some minerals are translucent, and can't be seen through, however light can be seen through it. Other minerals are opaque.
78
What are rock-forming minerals?
The most commonly found minerals on the planet, that make up most of the rocks of Earth's Crust.
79
What are the 8 elements that make up 98% of the Earth's crust.
In order of abundance: oxygen(O) 46.6%, silicon(Si) 27.7%, aluminum(Al) 8.1%, iron(Fe) 5.0%, calcium(Ca) 3.6%, sodium(Na) 2.8%, potassium(K) 2.6%, and magnesium(Mg) 2.1%. All other elements make up 1.5% of the earth's crust.
80
What elements combine to form the frame-work of the most common mineral class? What is the most common mineral class?
Silicon and Oxygen make up the most common mineral class, the Silicates.
81
What is the second most common mineral class?
The Carbonates are the second most common mineral class.
82
What element is the most prominent member of the Carbonates?
Calcite is the most prominent member of the Carbonates.
83
What is the fundamental building block all silicates are made of?
The silicon-Oxygen Tetrahedron. This structure consists of four oxygen ions (each with a 2- charge) surrounding a much smaller silicon ion with a 4+ charge.
84
What are the more complex silicate structures?
Tetrahedra can link together by sharing oxygen ions to form single chains, double chains, and sheet structures.
85
Why are silicates the most common mineral class?
Because there are hundreds of varieties each with their own diagnostic properties.
86
What are some common silicate minerals?
Quartz, Hornblende, Feldspar.
87
What is the most common igneous rock on the continents?
Granite, a rock made up of silicate minerals. (quartz, feldspar, hornblende)
88
What silicate mineral is made up of only silicate tetrahedra?
Quartz
89
What is the Oxide, Magnetite used for?
It's an ore of iron (hematite), used for pigments.
90
What is the Sulphide, Pyrite used for?
Pyrite is fools gold, it is used for sulfuric acid production.
91
What is the Sulphate, Gypsum used for?
Gypsum is used for plaster production.
92
What is the Halide, Fluorite used for?
Flux for steal, and in toothpaste.
93
What is an evaporite mineral?
Evaporite minerals have high solubility.
94
What is Halite?
The mineral form of sodium chloride, NaCl. Chlorine acts as the negative ion. Commonly known as Rock Salt.
95
What are Halite's physical properties?
Perfect cubic cleavage (3 cleavage planes at 90 degrees), glassy lustre, ~2-2.5 hardness, salty taste and highly soluble.
96
What are Metallic Bonds?
Bonds that are formed when two or more metals combine. Valence electrons are shared, however metals tend to have few valence electrons, resulting in a "Sea of Electrons". Metallic Bonds are loosely held and can drift apart.
97
What is Fluorite?
Fluorite is a halide mineral containing with fluorine as the negative ion.
98
What is sylvite?
Sylvite is a halide mineral that is deposited as evaporites in shallow warm seas hundreds of millions of years ago. It is made of potassium chloride, KCl. It is processed to form potash, a chemical fertilizer.
99
What is a use for the Carbonate, Calcite?
Calcite is used in cement production and in flux.
100
What is a use for the Carbonate, Dolomite?
Dolomite is used in cement production and in flux.
101
What is a use for the Carbonate, Malachite?
Gemstone
102
What is a use for the Carbonate, Azurite?
Pigment
103
How can the chemical formula of a mineral vary without changing the mineral?
Elements that are very similar to one another can substitute for the element that is normally used. For example, ions of iron, Fe 2+ and Magnesium Mg 2+ are nearly the same size and can substitute for each other without altering the mineral structure.
104
What ion often substitutes for silicon in silicate tetrahedrons?
Aluminum Al 3+
105
What is the most abundant silicate mineral?
The feldspars. They take up more than 50% of the Earth's crust.
106
How do Silicates cleave?
Because silacon-oxygen bonds are strong, silicate minerals tend to cleave between the silcon-oxygen bonds rather than across them
107
How are most Silicates formed?
They crystalize when magma cools and solidifies. This can occur at or near the Earth's surface where there is low temperature and pressure, or at great depths where there is high temperature and pressure. The mineral that is produced depends largely on the composition of the magma.
108
What is a way that Silicates can form that doesn't involve magma?
When pre existing silicates at the Earth's surface undergo extreme pressure associated with mountain building.
109
What non Silicates are commonly found in thick layers?
Balite, Sylvite, and Gypsum
110
What are dark silicates?
Ferromagnesian Silicates. They are minerals that contain ions of iron or magnesium or both in their structure. Because of the iron content, they are dark in colour and have greater specific gravity.
111
What is the most common dark silicates?
Olivine, the pyroxenes, the amphiboles, the dark mica (biotite) and dark garnet.
112
Describe Olivine.
Olivine is a black to olive-green mineral with a glassy lustre and a conchoidal fracture. They are an important part of the earth's mantle. Olivine lacks a cleavage, and forms in small, rounded crystals.
113
Describe the pyroxenes.
A group of complex minerals that are important components of dark igneous rocks.
114
Describe Augite.
Augite is a pyroxene that has two directions of cleavage that meet nearly at a 90 degree angle. It is a dark mineral that has a crystalline structure of single chains of tetrahedra. Augite is one of the dominant minerals in basalt, a common igneous rock of oceanic crust and volcanic areas on continents.
115
Describe Hornblende.
Hornblende is a amphibole mineral that is usually a dark green to black colour and has two directions of cleavage that intersect at 90 degrees. Hornblende always cleaves at angles of 60 and 120 degrees. Hornblende often forms elongate crystals.
116
Describe Biotite.
A dark, iron riched member of the mica group. Biotite possesses a sheet structure that gives it an excellent cleavage in one direction. It has a shiny black appearance.
117
Describe Garnet.
Similar to Olivine in structure, in that it is composed of individual tetrahedra linked by metallic ions. It has a glassy lustre, lacks cleavage, and possesses conchoidal fracture. The most common colour of garnet is brown-deep red however it can vary. It forms equidimensional crystals that are most commonly found in metamorphic rocks.
