Download - Ch2 Minerals
Chapter 2
Minerals
What is Matter
Matter is anything that has mass and volume.
OR: you could sayanything that has weight and
takes up space.
Matter
Mass: is the amount of
material is a substance or object.
Volume: is the amount of
space taken up by a substance or object.
Matter
Weight: is the force of gravity on an object or substance.
Elements and Atoms
Elements are: substances that
cannot be broken down into simpler substances by ordinary chemical means.
EX: nitrogen, gold, iron, and etc.
Each Element has a
Symbol each symbol is based on the Greek
or Latin alphabet. WHY? EX: gold - Au, oxygen - O, helium -
He, Potassium - K, hydrogen - H
John Dalton
Atomic Theory He believed that each element was
made of tiny particles called atoms.
Atoms are made of:
protonsneutronselectrons
+0 or no charge
-
Parts of an Atom
Each electron is in an orbital or shell. Each orbital can contain only a certain number of electrons.
nucleus
Orbital or shell
Parts of an Atom
99.9% of an atom is the nucleus
Most atoms
tend to have a neutral charge. This usually means that they have the same number of protons and electrons
(6) protons - (6) electrons = neutral charge
Atomic Number
the number of protons in an atom
Mass Number
Gives the average number of protons and neutrons in an atom.
Atomic # - mass # = # of neutrons
Isotopes
are atoms of the same chemical element that have different mass numbers ( different number of neutrons).
Compound
2 or more elements chemically combined.
The smallest part of a compound is a molecule
H20 is the formula for 1 molecule of water.
Compounds
H2SO4 is the formula for 1 molecule of sulfuric acid.
CO2
HClNaCl
What is a Mineral?
1. Occur naturally2. Is a solid3. Has a definite chemical
composition4. Has its atoms arranged in an
orderly pattern5. Is inorganic
Minerals
May be elements or compounds
Most common elements in the crust are……...
1. Oxygen2. Silicon3. Aluminum4. Iron5. Calcium6. Sodium
Bonding
Most minerals are composed of 2 or more elements or bonded together.
Ion - is a charged atom. 1 more electron then total of protons
gives a negative charge to the atom.
Types of Bonding
Ionic bonding - forms when electrons are gained or lost
metals - make good positive ions ( loose electrons)
non-metals - make good negative ions (gain electrons)
Types of Bonding
Covalent bonding - forms when electrons are shared
oxygen and silicon share electrons
Metallic bonding – forms when electrons are shared by metal ions
Noble Gases
These gases do not share electrons readily. Therefore they generally do not form bonds.
How minerals form
1. Volcanism - magma heating and cooling.
2. Precipitation - when water evaporates some of the dissolved substances in the water crystallize.
3. Pressure and Temperature – form when existing minerals are subjected to changes in pressure and temperature. The atoms rearrange.
4. Hydrothermal Solutions – Chemical reactions take place when warm hydrothermal solutions come in contact with existing minerals. Also, when these solutions cool they can crystallize into new minerals.
Mineral Groups
These groups are classified in groups according to their composition.
Silicates – Silicon and oxygen form a silicon-oxygen tetrahedron. – 90% of all the minerals in the crust
are:
silicates
Carbonates – are minerals that contain the elements carbon, oxygen, and one other metallic element.
Oxides – are minerals that contain oxygen and one or more other elements, which are usually metals.
Sulfates and Sulfides – minerals that contain the element sulfur.
Halides – minerals that contain a halogen ion plus one or more other elements.
Native Elements – a group of minerals that exist in relatively pure form. Gold, silver, copper, sulfur, graphite
Crystals
Crystals are solids with a regular geometric shape. Each side is called a face.
Crystal size depends on how slowly or quickly they form. Slower cooling produces larger crystals.
Crystals
The crystalline structure of a mineral is dependent upon the bonding of the various atoms and ions.
Bonds determine crystal shape or better the molecular shape.
Crystalline Shapes
CUBIC ORTHORHOMBIC
Cubic
Halite
Graphite vs. Diamond
Graphite
Crustal Minerals
90% of all the minerals in the crust are:
silicates These form silica tetrahedron