Part II. How to build a planet (continued) Atoms, Compounds, and minerals:
C. Earth is made of minerals.
1. What is a mineral?
- Physical properties of minerals.
(Crystal structure and composition are the 2 parameters that determine what mineral forms and control physical properties.)
- Luster.
- Cleavage.
- Crystal faces
- Hardness.
- Color
- Specific gravity (density).
- Special properties (magnetism, taste, reaction with acid)
D. How to build a crystal.
1. Composition.
a. Atom: the smallest unit of an element. It is hard to imagine, but an individual atom of an element would exhibit the properties of the element.
i. Examples: hydrogen, carbon, iron, aluminum, sulfur, uranium.
ii. More than 106 elements known.
iii. 92 occur naturally on Earth.
iv. Structure:
- Nucleus (protons and neutrons)
- most of the atom's mass.
- The number of PROTONS identify/define the element.
- The number of neutrons determines the isotope of the element.
- Electrons:
- Found in a cloud around the nucleus.
- Have almost no mass.
- The number and their orbital energy determine the chemical characteristics of the atom / element.
Check out this article in National Geographic that shows a recently discovered cave in Mexico that has gypsum crystals up to 36 feet long! Here are some more photos from this cave.
Week 3: Study Questions
Atoms, Compounds, and minerals:
Practice questions:
1. Which of the following determines (or identifies) an element?
2. The following are examples of minerals EXCEPT:
3. Sulfur is a major component of which mineral listed below?
Answers:
Part II. Atoms, Compounds, and Minerals
1. = The number of protons.
2. = coal.
3. = galena.
In addition to your lecture notes and textbook check out: this web page that has everything you ever wanted to know about your favorite mineral.
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