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