Chapter 2: 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 atomloses an electron(becomes positively

Charged ION)

Chlorine atomgains 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

• 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 matrimony

• Ionic bonding:– electrons are transferred between atoms

forming attracting ions (e.g., NaCl)

Na+ Cl–

Bonding – chemical matrimony

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

Periodic Table of Elements

Bonding – chemical matrimony

• Covalent bonding:– electrons are shared between atoms

– generally strong bonds

(e.g., diamond, pure C)

Chlorine gas molecule, Cl2

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

What kind of bonding do you prefer?

In a covalent world… In an ionic world…

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 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 formulaexamples: 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%