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)

Chlorine atom gains an electron (becomes negatively

charged)

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 marriage

• Chemical bonding: – formation of a compound by combining two or

more elements – manner in which electrons are distributed among

atoms

• In bonded atoms, electrons may be lost, gained, or shared.

• 4 types of bonding: ionic covalent metallic van der Waals

Bonding – chemical marriage

• Ionic bonding: – electrons are transferred between atoms forming

attracting ions (e.g., NaCl)

Na+ Cl–

Bonding – chemical marriage

• Ionic bonding: – orderly arrangement of oppositely charged ions – bonds are moderately strong (salt dissolves in water)

Bonding – chemical marriage

• Covalent bonding: – electrons are shared between atoms

– generally strong bonds (e.g., diamond, pure C)

Chlorine gas molecule, Cl2

Bonding – chemical marriage

• 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 marriage

• 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

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 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

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%