minerals ( earth science)

8/12/2019 Minerals ( Earth Science)

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Prentice

HallEARTH SCIENCE

Tarbuck Lutgens


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Chapter

2

Minerals


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Elements and the Periodic Table

2.1 Matter

Elementsare the basic building blocksof minerals.

Over 100 elements are known.


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Atoms

Smallest particles of matter

2.1 Matter

Have all the characteristics of an element

neutrons, which have neutral electrical charges

The nucleusis the central part of an atom

and containsprotons, which have positive electrical charges


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Atoms

2.1 Matter

Energy levels, or shellssurround the nucleus

contain electronsnegatively charged particles

The atomic number is the number of protonsin the nucleus of an atom.


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Model of an Atom


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Isotopes

Many isotopes are radioactive and emit energyand particles.

Isotopes of an element have the same numberof protons but varying numbers of neutrons.

Have different mass numbers: the sum of the

neutrons plus protons

2.1 Matter

The mass number is the number of neutrons and

protons in the nucleus of an atom.


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Why Atoms Bond

A compoundconsists of two or moreelements that are chemically combined inspecific proportions.

When an atoms outermost energy leveldoes not contain the maximum numberof electrons, the atom is likely to form achemical bondwith one or more atoms.

2.1 Matter

An ionis an atom that gains or loses electrons.


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Types of Chemical Bonds

1.Ionic bonds form between positive and

negative ions.

2.1 Matter

2.Covalent bonds form when atoms share

electrons.

3.Metallic bonds form when metal ions

share electrons.


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How Minerals Form

2.2 Minerals

1. Crystallization from magma2. Precipitation

3. Pressure and temperature

4. Hydrothermal solutions


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Minerals Formed as a Result of

Crystallization of Magma


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Mineral Groups

Can be classified based on their

composition

2.2 Minerals

1. Silicates

Silicon and oxygen combine to form a structure

called the silicon-oxygen tetrahedron. Thissilicon-oxygen tetrahedron provides the

framework of everysilicate mineral.


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The Silicon-Oxygen Tetrahedron


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Silicon-Oxygen Chains, Sheets,

and Three-Dimensional Networks


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Mineral Groups

2.2 Minerals

2. Carbonates

Minerals that contain the elements carbon,

oxygen, and one or more other metallic

elements

3. Oxides Minerals that contain oxygen and one or more

other elements, which are usually metals


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Mineral Groups

2.2 Minerals

4. Sulfates and Sulfides

Minerals that contain the element sulfur

5. Halides

Minerals that contain a halogen ion plus one or

more other elements6. Native elements

Minerals that exist in relatively pure form


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Sulfides


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Native Copper


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Color

2.3 Properties of Minerals

Small amounts of different elements cangive the same mineral different colors.


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Streak


Streakis the color of a mineral in itspowdered form.


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Luster


Lusteris used to describe how light isreflected from the surface of a mineral.

P it (F l G ld) Di l


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Pyrite (Fools Gold) Displays

Metallic Luster.


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Crystal Form


Crystal formis the visible expressionof a minerals internal arrangement of

atoms.

Q t Oft E hibit


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Quartz Often Exhibits

Good Crystal Form.


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Hardness


Hardnessis a measure of theresistance of a mineral to being

scratched.

Mohs scaleconsists of 10 minerals

arranged from 10 (hardest) to 1 (softest).


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Mohs Scale of Hardness


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Cleavage


Cleavageis the tendency of a mineral tocleave, or break, along flat, even

surfaces.


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Mica Has Cleavage in One Direction


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Conchoidal Fracture


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Density


Density is a property of all matter thatis the ratio of an objects mass to its

volume.


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Distinctive Properties of Minerals


Some minerals can be recognized byother distinctive properties.

minerals ( earth science)

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