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Describe the makeup of the two simplest atoms, hydrogen (atomic number 1) and helium (atomic number 2).
2.2 How much of the mass and how much of the volume of an atom are in the nucleus?
What is the ratio of protons to electrons in an atom, and what is the net electric charge of an atom?
How is the atomic number of an atom determined?
How is the atomic weight (mass number) of an atom determined?
There are three types of oxygen—160, 170, and 180. What are these varieties called?
Hydrogen has three isotopes—1H, 2H, and 3H. How do they differ?
Uranium 238 (238U), the heaviest naturally occurring element, has an atomic number of 92. How many protons, neutrons, and electrons does it have?
Uranium has another isotope with an atomic weight of 235 (235U). How many protons, neutrons, and electrons does it have?
Some isotopes undergo radioactive decay and are called radioactive isotopes. For example, 238U (uranium) decays to 206Pb (lead). How does this happen?
The process described in Problem 2.11 is a nuclear reaction because it involves changes in the nucleus. Is it nuclear fusion or nuclear fission?
What are the differences in the two nuclear processes, fission and fusion?
What is the significance of Einstein’s equation, E = mc2?
Explain the statement, “Energy and mass are two aspects of the same thing.”
When four hydrogen nuclei, each composed of one proton, join to make one helium nucleus of two protons and two neutrons (as in Problem 2.13 above), the mass of the helium nucleus is calculated to be less than the mass of the original four protons, by the amount of 0.0029 mass units. What is the significance of such a mass “loss”?
How are elements probably formed?
What is the source of the sun’s energy?
Why are ions important geologically?
The electrons of atoms are arranged in three-dimensional energy-level “shells” or spheres. What is the stable maximum number of electrons in the outer energy-level shell of an atom?
Atoms “strive toward stability” by trying to fill the outer energy-level shell to the maximum stable number of 8. This is commonly illustrated by the bonding of sodium and chlorine atoms (Fig. 2.2). Explain how this happens.
Refer to Fig. 2.2. After sodium gives an electron to chlorine, are they still electrically neutral atoms? All diagrams are included in the solution file.
What is the compound that results from the chemical reaction illustrated by Fig. 2.2? See Fig. 2.3. All diagrams are included in the solution file.
Why are the inert gases—neon, krypton, radon, xenon, and argon—inert, thereby seldom participating in chemical reactions to make compounds?
What type of chemical bonding is illustrated by Fig. 2.2
Explain the other geologically important type of chemical bonding, covalent bonding; give an example.
Diamond and graphite are both pure carbon. Yet diamond is the hardest natural substance and graphite is one of the softest. Why?
Does graphite have a good cleavage?
Are petroleum and water minerals?
The mineral halite is shown in Fig. 2.3. How many cleavages does it have, and what are their relationships to each other?
In Fig. 2.3, two models of halite are shown. One is an “exploded” model which enables one to see the location of the ions in the crystal structure. The model on the right shows the actual positioning of the ions next to each other. How do mineralogists know that the ions touch?
What are the two main factors that determine which ions of the many types present in a watery solution or in a magma will be bonded together to form minerals?
Note the ionic radii and ionic charges of the eight most common ions in the earth’s crust in Table 2.1. Which pairs of ions have very similar sizes and charges and can substitute easily for each other in a crystal structure?
Which of the eight common elements is most abundant in the earth’s crust, hydrosphere, and atmosphere? (See Table 2.2.)
Note from Table 2.3 that the most common minerals in the earth’s crust are all silicates. The basic building block is the silicon-oxygen tetrahedron (see Fig. 2.4). What is the net electric charge of the tetrahedron and why is this geologically important?
What is illustrated by Fig. 2.5?
Why are quartz and the feldspars (plagioclase and orthoclase) such hard minerals?
Name the main mineral groups, based on composition.
The 8 common rock-forming minerals are listed in Table 2.3. If the list were of the 10 most common minerals, which two should be included?
A major principle is illustrated by the “rock cycle” in Fig. 2.6, although it may not be readily apparent. Think about it, and then see if the answer does indeed make sense.
The three main groups of rocks, based on origin, are shown on Fig. 2.6. Describe each.
What elements form the oxide mineral group? Give an example.
What elements form the carbonate mineral group? Give an example.
What elements form the sulfide mineral group? Give an example.
What elements form the sulfate mineral group? Give an example.
What elements form the chloride mineral group? Give an example.
A few minerals consist of elements in the pure (native) state, not combined with other elements. Name four examples.
Minerals crystallize in six crystal systems. Name them.
What is the streak of a mineral?
The silicon-oxygen tetrahedron is the basic building block of the silicates, and one might guess that all silicate mineral formula would end with Si04. Instead, the specific formulas of the common silicates contain different ratios of silicon to oxygen. Why?
The feldspars are the most important minerals in the earth’s crust. They are similar to quartz in that all the oxygens of the tetrahedral are shared. How do they differ from quartz?
One of the common rock-forming minerals is plagioclase feldspar which contains variable amounts of Na and Ca in addition to Al, Si, and 0. Pure Na-plagioclase has the formula NaA1Si3O3. Because the sizes of Nat+1 and Cat+2 ions are similar (see Table 2.1), Cat+2 can substitute for Na+1. Would the formula of Ca-plagioclase be CaAlSi3O8? Explain.
Most plagioclase contains both Na and Ca. How is the apparent charge imbalance accommodated? (Hint: The solution involves more ionic substitutions.)
See Fig. 2.3. Which sodium ion belongs to which chlorine ion in a halite “molecule” of NaCI?
How are the harnesses of minerals determined?
What is metallic bonding?
A 100-g nugget of gold that you found panning in a stream in the mountains seems to be pure, but you wonder whether there might be some quartz in the center. You drop it (carefully) into a graduated cylinder and note that it displaces 5.2. cm3 (cubic centimeters) of water. Calculate its density.
At a glance, quartz and calcite may look alike. What physical properties distinguish them?
The alchemists of past centuries were always looking for a magical way to change lead into gold. With nuclear reactions, how would a modern alchemist try to accomplish this transition? (One isotope of lead has 82 protons and 125 neutrons, whereas gold has 79 protons and 118 neutrons.)
Name the main physical properties of minerals
A quartz crystal is illustrated in Fig. 2.7. Which crystal system does it represent? (
What are the three “spheres” at or near the earth’s surface, excluding the biosphere?
How thick is the atmosphere?
Where is most of the water of earth’s hydrosphere found?
What percent of the earth’s surface is covered by oceans and seas?
What are the major large-scale topographic features on the continents?
When the earth’s surface is drawn to scale, are the mountains prominent features?
What are the two major large-scale, high-relief topographic features on the ocean floors?
What relationships do earthquakes and volcanoes have to ridges and trenches?
What is the common spatial relationship of volcanic island arcs (such as the Aleutian Islands and the Philippine Islands), volcanic arcs on land (such as the Andes of South America and the Cascades of North America), and oceanic trenches?
What are the relationships of the continental shelves, continental slopes, and the deep oceanic basins? (See Fig. 1.3)
How wide are the continental shelves?
Are the shorelines of the continents the edges of the continents?
What are the angles of slope, compared to a horizontal surface, of the continental shelves and the continental slopes?
Why continental slopes are always depicted in diagrams as quite steep, about 45 to 60°,
What are general figures for the depths of ocean water at (a) the outer edges of the continental shelves and (b) the bases of the slopes?
What are continental rises?
Where is sediment found in the oceans, and how thick is it?
What major features are found as deep “cuts” on the continental slopes? Give an example
How did submarine canyons originate?
What is the Mid-Atlantic Ridge?
What is the relief on the Mid-Atlantic Ridge? See Fig. 1.4.
Is there any expression of the Mid-Atlantic Ridge above sea level?
Where are the deepest points in the oceans?
What are seamounts and guyots?
Are the rock types that make up the continents and the ocean basins the same?
Was Christopher Columbus the first person to say that the earth was “round” rather than flat?
How did the Greeks determine that the earth was round?
What is the significance of the following equation?
Who derived the above equation?
Where would the force of gravitational attraction between the earth and a basketball be the greatest—on the equator or at the North Pole?
If the earth’s volume is 1.087 x 1027 cm3 and its mass is 6 x 1027 grams, what is the density of the earth?
How do scientists know that the earth is denser at depth than at the surface
What is the general nature of the earth’s interior?