GEOL 0820
Natural Disasters
Spring, 2025
LECTURE #3: Elements and Minerals
Date: 15 January 2025
I. Recitations start this week!
● please make sure you attend the class and talk with your TA about what is
expected
o this is a large percentage of your grade
■ and make sure that you have a copy of the recitation manual
" you will need this for the first recitation in order to complete the work
II.Next week
● no class on Monday (Jan.20th)-MLK day holiday
Ⅲ.New Topic:Atoms and Minerals
● from the really “big picture”to the VERY small one!
o from large-scale hazards to the scale of atoms
o we won't spend as much time on this subject as other introductory geology classes
you get a good review in the recitation this week (and rocks next week)
■ topics are useful for understanding how geology-focused natural disasters work
o critical for understanding the building blocks of geology
o next class
we'll examine how minerals combine into common rock types
important for particular types of disasters:Plate Tectonics,earthquakes and later,volcanoes and landslides
IV.Definitions and Concepts
● mineral: a naturally occurring,inorganic,solid,with a specific chemical composition,and a specific regular arrangement of atoms
o five parts to this very precise definition-make sure you know them
o minerals have specific physical and chemical properties
· identifying minerals and rocks takes practice and experience
o one of the harder skills to acquire for a geologist
o other courses in the Department of Geology devote more time and effort to these details
■ for example,there are five labs devoted to rocks and minerals in the Physical Geology Lab (GEOL 0055)class
· atom: smallest particle of an element that still retains the properties of that element
o an atom is made up of protons,neutrons and electrons
protons(+)and neutrons (o)form. the nucleus
■ electrons (-)orbit the nucleus
■ remember from the definition of a mineral:specific regular arrangement of atoms
● what is atomic structure?
o structure of minerals
all minerals are built from regular,repeating arrangements of atoms
■ this regular structure is what gives a mineral crystal its shape/form.
■ example:
a piece of wood is a solid
>but it has no regular arrangement of atoms
therefore,it is not a crystalline solid
glass,bricks,plastic,etc.are also not crystalline solids (and hence,are not minerals)
● what is an element?
o element: a substance that cannot be broken down into other substances
o atomic number
■ the number of protons in an atom
example:hydrogen(H)has 1 proton (atomic number:1)
example:oxygen(O)has 8 protons (atomic number:8)
· periodic table: arrangement of all elements by their atomic number (see below)