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CHAPTER 3 Minerals
1. All matter is composed of chemical elements, each of which consists of atoms. Individual
atoms consist of a nucleus, containing protons and neutrons, and electrons that circle the nucleus
in electron shells.
2. Atoms are characterized by their atomic number (the number of protons in the nucleus) and
their atomic mass number (the number of protons plus the number of neutrons in the nucleus).
3. If the two electrons in its outer electron shell of the element magnesium are lost,
what is the electrical charge of the magnesium ion?
4. What is the atomic mass number of a magnesium atom?
5. The atomic number of an element is determined by the:
a. number of electrons in its outermost shell;
b. number of protons in its nucleus;
c. diameter of its most common isotope;
d. number of neutrons plus electrons in its nucleus;
e. total number of neutrons orbiting the nucleus.
6. Bonding is the process whereby atoms are joined to other atoms. If atoms of different
elements are bonded, they form a compound. Ionic and covalent bonds are most common in
minerals, but metallic and van der Waals bonds also occur in a few.
7. Compare and contrast ionic and covalent bonding.
8. When an atom loses or gains electrons, it becomes a(n):
a. isotope; b. proton; c. ion; d. neutron; e. native element.
9. The sharing of electrons by adjacent atoms is a type of bonding called:
a. van der Waals; b. covalent; c. silicate; d. tetrahedral; e. ionic.
10. Those chemical elements having eight electrons in their outermost electron shell are the:
a. noble gases; b. native elements; c. carbonates; d. halides; e. isotopes.
11. The silicon atom has a positive charge of 4, and oxygen has a negative charge of 2.
Accordingly, the ion group (SiO 4) has a:
a. positive charge of 2; b. negative charge of 2; c. negative charge of 1;
d. positive charge of 4; e. negative charge of 4.
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12. Most minerals are compounds, but a few, including gold and silver, are composed of a single
element and are called native elements.
13. Define chemical compound and native element.
14. A chemical element is a substance made up of atoms, all of which have the same:
a. atomic mass number; b. number of neutrons; c. number of protons; d. size; e. weight.
15. All minerals are crystalline, meaning that they are solids that possess an orderly internal arrangement
of atoms.
16. How does a crystalline solid differ from a liquid and a gas?
17. Minerals are solids possessing an orderly internal arrangement of atoms, meaning that they
are: a. amorphous substances; b. crystalline; c. composed of at least three different
elements; d. composed of a single element; e. ionic compounds.
18. The basic building block of all silicate minerals is the:
a. silicon sheet; b. oxygen-silicon cube; c. oxygen-silicon tetrahedron; d. silicate double chain;
e. silica framework.
19. Some minerals vary in chemical composition because atoms of different elements can
substitute for one another provided that the electrical charge is balanced and the atoms are of
about the same size.
20. What accounts for the fact that some minerals have a range of chemical compositions?
21. The chemical formula for olivine is (Mg,Fe)2SiO4, which means that in addition to silica:
a. magnesium and iron can substitute for one another;
b. magnesium is more common than iron;
c. magnesium is heavier than iron;
d. all olivine contains both magnesium and iron;
e. more magnesium than iron occurs in the Earth's crust.
22. Why are the angles between the same crystal faces on all specimens of a mineral
species always the same?
23. In sheet silicates, individual sheets composed of oxygen-silicon tetrahedra possess a negative
electrical charge. How is this negative charge satisfied?
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24. The ratio of a mineral's weight to the weight of an equal volume of water is its:
a. specific gravity; b. luster; c. hardness; d. atomic mass number; e. cleavage.
25. Of the more than 3,500 known minerals, most are silicates. Ferromagnesian silicates contain
iron (Fe) and magnesium (Mg), and non-ferromagnesian silicates lack these elements.
26. What is a silicate mineral? How do the two subgroups of silicate minerals differ
from one another?
27. To which of the following groups do most minerals in the Earth's crust belong?
a. oxides; b. carbonates; c. sulfates; d. halides; e. silicates.
28. The two most abundant elements in Earth's crust are:
a. iron and magnesium; b. carbon and potassium; c. sodium and nitrogen;
d. silicon and oxygen; e. sand and clay.
29. In addition to silicates, several other mineral groups are recognized, including carbonates,
oxides, sulfides, sulfates, and halides.
30. The physical properties of minerals such as color, hardness, cleavage, and crystal form are
controlled by their chemical composition and crystal structure.
31. What do all carbonate minerals have in common?
32. Describe the mineral property of cleavage, and explain what controls cleavage.
33. Many minerals break along closely spaced planes and are said to possess:
a. specific gravity; b. cleavage; c. covalent bonds; d. fracture; e. double refraction.
34. A few minerals are common enough constituents of rocks to be designated rock-forming
minerals.
35. What are rock-forming minerals?
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36. An example of a common non-ferromagnesian silicate mineral is:
a. calcite; b. quartz; c. biotite; d. hematite; e. halite.
37. Calcite and dolomite are:
a. oxide minerals of great value;
b. ferromagnesian silicates possessing a distinctive sheet structure;
c. common rock-forming carbonate minerals;
d. minerals used in the manufacture of pencil leads;
e. important energy resources.
38. Many resources are concentrations of minerals of economic importance.
39. Reserves are that part of the resource base that can be extracted economically.
atom
matter
atomic mass number
metallic bond
atomic number
mineral
bonding
native element
carbonate mineral
neutron
cleavage
non-ferromagnesian silicate
compound
nucleus
covalent bond
proton
crystalline solid
reserve
electron
resource
electron shell
rock
element
rock-forming mineral
ferromagnesian silicate
silica
ion
silica tetrahedron
ionic bond
silicate
isotope
van der Waals bond