Chapter 2: Matter and Minerals

1. Chapter 2: Matter and Minerals

2. 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

3. 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

4. Periodic Table of Elements

5. 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

6. 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.

7. Atomic Structure

8. Periodic Table of Elements Atomic Number (# of protons) Mass number= # protons + # neutrons YES These are called isotopes. Example: (Carbon) 12C 13C 14C Can atoms of the same element have different mass numbers? Atomic weight = # protons + average # neutrons

9. 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

10. 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

11. 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

12. Compounds • Definition: • A chemical compoundconsists 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.

13. 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: ioniccovalentmetallicvan der Waals

14. Bonding – chemical matrimony • Ionic bonding: • electrons are transferred between atoms forming attracting ions(e.g., NaCl) Na+ Cl–

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

16. Periodic Table of Elements

17. Bonding – chemical matrimony • Covalent bonding: • electrons are shared between atoms • generally strong bonds (e.g., diamond, pure C) Chlorine gas molecule, Cl2

19. 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

20. Bonding – chemical matrimony • Van der Waals bonding: • sheets of covalently bonded atoms held together by weak electrostatic forces • very weak bonds examples: graphite, mica

21. What kind of bonding do you prefer? In an ionic world… In a covalent world…

22. The stuff that makes up all matter • The make-up of solid matter on Earth: Atoms  ElementsCompoundsMineralsRocks (smallest) (largest)

23. 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

25. Mineral characteristics • Definition of a Mineral: • naturally occurring • inorganic • solid • characteristic crystalline structure • definite chemical composition steel plastic sugar table salt mercury ice coal no, #1 no, #1 no, #1,2 YES! no, #3 YES! no, #2 basalt obsidian mica gold paper chalk coral no, #5 no, #4 YES! YES! no, #1,2 no, #2 no, #2

26. 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

27. Mineral characteristics • Characteristic crystalline structure • must have an ordered arrangement of atoms • displays repetitive geometric patterns in 3-D glassnota 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

28. How many minerals are there? • Only ~30 occur commonly (whew!) • Why not more? • Some combinations are chemically impossible • Relative abundances of elements don’t allow more • Nearly 4,000 types of minerals

29. Element abundances in the crust All others: 1.5%