Answer to Question 1
Answer: Minerals are most important if they are common in rocks, provide essential resources, or both. Silicate minerals are the primary rock-forming minerals in the crust. More than 4,000 minerals have been identified, but only a few dozen are important as rock-forming minerals, because only 12 of the 89 naturally occurring elements compose 99.7 percent of Earth's crust. However, most economically valuable metals are processed from nonsilicate ore minerals, especially oxide and sulfide minerals, so not only silicate minerals are important
Answer to Question 2
Answer: Most of the size of an atom consists of the cloud of electrons that orbit the nucleus. If many electrons exist in a small area around the nucleus, then there is a good chance that electrons fired in the TEM will collide with an orbiting electron and bounce off it, rather than continuing through to the detector. If, however, the electrons are widely spaced around a nucleus, then the fired electrons may pass through the atom without hitting any obstacles. This means that the shadows in the TEM image may not represent all of the types of atoms in a mineral, but rather only the atoms with closely clustered electrons.
Figure 7.1 shows the rapid decline in the trust of Americans in government since the 1960s. This de
It is important that parents repeat safety rules to preschoolers and monitor compliance with rules.
What are examples of ideal forms?
Step 8 is very important. Be sure that the customer’s concern has been corrected.
Climate change is an important vector for human diseases
Red, fleshy fruits of hawthorn plants (Crataegus) are an important food for cedar waxwings (Bombycil