Minerals 2015
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Transcript of Minerals 2015
Matter and Minerals
What is Matter?
• Matter – the substance of which any physical
object is composed
States of Matter:
• Solid
• Liquid
• Gas
Controlling factors:
• Temperature
• Pressure
Examples: Gold Mercury Oxygen
solid liquid gas
The stuff that makes up all matter
• The make-up of solid matter on Earth:
Atoms Elements Compounds Minerals Rocks
(smallest) (largest)
• Elements:
– fundamental building blocks
– smallest matter that can’t be broken down
Periodic Table of Elements
The stuff that makes up all matter
• The make-up of solid matter on Earth:
Atoms Elements Compounds Minerals Rocks
(smallest) (largest)
• Atoms:
– the stuff that builds elements
– the smallest particle that uniquely defines an element
Atomic Structure
• Particles that make up an atom:
– Protons: positive (+) charge
– Neutrons: no charge
– Electrons: negative (-) charge
Protons + neutrons define the nucleus of an atom.
Layers of electrons that orbit around the nucleus
are called orbitals or energy-level shells.
Atomic Structure
YES
These are called isotopes.
Example: (Carbon) 12C 13C 14C
Periodic Table of Elements
Atomic Number (# of protons)
Mass number = # protons + # neutrons
Can atoms of the same element have
different mass numbers?
Atomic weight =
# protons + average # neutrons
Atomic Structure
• Atoms of the same element:
• have the same number of protons
(i.e., same atomic number)
• can have different numbers of neutrons
(referred to as isotopes)
• can have different numbers of electrons
• Ion – an atom that has gained or lost an electron
Atomic Structure
Sodium atom
loses an electron(becomes positively
Charged ION)
Chlorine atom
gains an electron(becomes negatively
Charged ION)
An Ion is a particle that is electrically charged (positive or
negative); an atom or molecule or group that has lost or gained
one or more electrons
Atomic Structure
• Types of IONS:
• CATIONS – a loss of electrons, resulting
in a positive (+) charge
• ANIONS – a gain of electrons, resulting
in a negative (-) charge
Examples: Na+ (cation) Cl–
(anion)
NaCl (table salt)chemical compound
Compounds
• Definition:
– A chemical compound consists of elements
that combine in a specific ratio.
Examples: NaCl H2O
• The smallest quantity of a compound is
called a molecule.
• Molecules are held together by chemical
bonding.
Bonding – chemical matrimony
• Ionic bonding:
– orderly arrangement of oppositely charged ions
– bonds are moderately strong (salt dissolves in water)
Bonding – chemical matrimony
• Metallic bonding:
– electrons drift around from atom to atom(e.g., copper, gold, silver)
– good conductors of electrical current
– generally weaker, less common than other bonds
Gold, Au
Bonding – chemical matrimony
• Van der Waals bonding:
– sheets of covalently bonded atoms held together by weak electrostatic forces
– very weak bonds
examples: graphite, mica
Atoms Elements Compounds Minerals Rocks
(smallest) (largest)
The stuff that makes up all matter
• The make-up of solid matter on Earth:
Minerals: the building blocks of rocks
• Definition of a Mineral:
naturally occurring
inorganic
solid
characteristic crystalline structure
definite chemical composition
• Definition of a Rock:
• A solid aggregate (mixture) of minerals
Physical Properties of Minerals
1- Optical Properties
Color
Streak
Luster
Diaphaneity
2- Cohesive Properties
Hardness
Cleavage
Parting
Fracture
Tenacity
3- Sense Properties
Touch
Odour
Teste
4- Specific Gravity 5- Other Properties such as: Magnetism, Electricity,
Radioactivity, Fusibility and Solubility
Mineral characteristics
• Definition of a Mineral:
1. naturally occurring
2. inorganic
3. solid
4. characteristic crystalline structure
5. definite chemical composition
steel plastic sugar table salt mercury ice coal
basalt obsidian mica gold paper chalk coral
no, #1 no, #1 no, #1,2 YES! no, #3 YES! no, #2
no, #5 no, #4 YES! YES! no, #1,2 no, #2 no, #2
Mineral characteristics
• Naturally formed
– No substance created artificially is a mineral.
examples: plastic, steel, sugar, paper
• Inorganic
– Anything formed by a living organism and
containing organic materials is not a mineral.
examples: wood, plants, shells, coal
• Solid
– Liquids and gases are not minerals.
examples: water, petroleum, lava, oxygen
Mineral characteristics
• Characteristic crystalline structure
– must have an ordered arrangement of atoms
– displays repetitive geometric patterns in 3-D
glass not a mineral (no internal crystalline structure)
• Definite chemical composition
– must have consistent chemical formula
examples: gold (Au), quartz (SiO2), orthoclase (KAlSi3O8)
basalt (like many other rocks) contains variable ratios
of different minerals; thus, has no consistent formula
– Only ~30 occur commonly (whew!)
– Why not more?
• Some combinations are chemically impossible
• Relative abundances of elements don’t allow more
How many minerals are there?
• Nearly 4,000 types of minerals
Element abundances in the crust
All others: 1.5%