1. Chapter 5: Atoms to Minerals

2. Chapter 5.1

3. Matter and Atoms

4. Matter
Anything that has mass (amount of material) and volume (amount of space an object takes up)
Ordinary matter is composed of elements (a substance that cannot be broken into a simpler substance by ordinary chemical means)
200 years ago, John Dalton stated that “each element is made up of tiny particles, all alike, called atoms”
Dalton describes an atom as the smallest part of an element that has all the elements properties.

5. Structure of an atom
In its normal state, a neutral atom as an equal number of electrons and protons
Atomic # tells how many protons are in the nucleus and is equal to the # of electrons in the electron cloud
The nucleus has 99.9% of the atoms mass
Energy levels of electrons represents how many electrons each level can hold 2, 8, 18, 32, 21, 9, and 2

6. Classifying Atoms Periodic table of elements p. 698
Rows represent the increasing number of protons
Vertical columns group these elements that have similar chemical properties
Mass #; sum of protons and neutrons

7. Isotope – an atom with a different # of neutrons
Potassium
Atomic Number 19
Symbol K
Atomic Mass
39.10 amu
K has 19 protons (atomic number)
20 neutrons (atomic mass – atomic # [39 – 19])
19 electrons; always equals the of protons

8. Bonding of Atoms
Most substances on earth are not pure they are compounds – contains atoms of 2 or more elements.
For a substance to be stable it likes its last electron level to be filled so they fill it by losing or gaining electrons
Covalent Bonds – share electrons

9. Ionic Bonds – when atoms loose or gain an electron they became charged.
Gained; [-] Charge
Lost; [+] Charge
The opposite charge will then attract
Ion – a charged atom
A metal looses electrons easily to form positive ions. Therefore they can not join with other metals.
Nonmetals gain electrons easily to form negative ions. This makes them want to bond to the positive metals.

10. Metallic Bonds – The bonds that form between metals cause the electrons to move around all the positive ions.

11. Compounds and Mixtures
Compounds can have properties entirely unlike those of the elements of which it is made.
Salt NaCl Sodium and Chlorine are both poisonous to humans when separated
Compounds can only be separated by chemical means.
Mixtures – elements keep their own properties
Salt water – water can be separated by boiling

12. Sodium
Metal +
Chlorine
Gas
Halite
(Table Salt) =

13. Chapter 5.2

14. Composition and Structure of Minerals

15. What is a mineral? A mineral must be Naturally occurring Solid
Definite chemical composition
Orderly arrangement of atoms
Inorganic (never alive)
Most minerals are compounds
Quartz SiO2; Silicon and Oxygen
Native elements – minerals with a single element
Gold (Au), silver (Ag), copper (Cu), Sulfur (S), diamond (C)
Rock – different types of minerals and native elements mixed together

16. Diamond (C)
Silver (Ag)
Copper (Cu)
Gold (Au)
Sulfur (S)
Native Elements

17. How minerals form
Many minerals form from molten rock in which the atoms can move freely. Once it begins to cool the ions move closer together to form chemical bonds
Many different minerals will form. The composition of the magma will control what type form.
The slower the magma cools the larger the grains.
Can also form from evaporating water – salt
New minerals will form when existing minerals are exposed to more heat and pressure.

18. Structure of Minerals Crystal Structures
The orderly arrangement of atoms in a mineral often seen as the minerals shape
Salt p. 98
Crystal is a regular geometrical solid with smooth surfaces called crystal faces.
Each mineral has its own crystal form
There are six basic shapes p. 99

19. Silicates – minerals that are compounds including silicon and oxygen
They also may contain a metal atom
Silica tetrahedron – 4 oxygen surrounding 1 silicon

20. Crystal Structures and Physical Properties
Cleavage – tendency to split along definite planes
Hardness – resistance to scratch. Sometimes the same element can have different hardness based on its internal structure
Diamond – pure carbon very hard
Graphite – pure carbon very soft

21. Chapter 5.3

22. Identifying Minerals
Mineralogy – study of minerals and their properties

23. Rock Forming Minerals

24. Identifying Minerals by Inspection
Very rarely are minerals Id. by one property
Types of Properties
Color – easily observed but, least useful
Luster – how a mineral reflects light
2 basic types
Metallic
Nonmetallic
Crystal shape

25. Streak – color of a powdered mineral
Metallic minerals streak is at least as dark as a specimen
Nonmetallic – colorless or white
Cleavage – minerals splits along flat surfaces

26. Fracture – breaks in directions other than cleavage planes
Conchoidial - shell like fracture
Splintery – jagged surface
Uneven – rough surface
Hardness – resistance to scratch
Mesh’s hardness scale 1- 10

27. Chapter 5.4

28. Mineral Groups

29. Major Silicates 90% of the minerals in earth’s crust are silicates
Quartz – used in watch movements, prisms, heart lamps, lenses, glass and paints. Crystals are considered semiprecious
Feldspars – used aluminum atoms in place of some of the silicon which become balanced by other metals. It is used in glass and ceramics
Micas (biotite and muscovite) used as electronic insulators, paints, plastics, rubber and roofing.

30. Biotite
Quartz
Feldspar
Silicates

31. Ferromagnesium Silicates
Olivine – gem quality is known as peridote
Kaolinite – is pure white, a clay compound used in ceramics, paint and fiberglass also known as china clay

32. Carbonates – negative carbonate ions bonded to positive metal ions which are used construction. Calcite and Dolomite give us rock like limestone and marble.

33. Oxides – Iron bonded with oxygen of sulfur (sulfide)
Hematite – iron oxide used to make steel medicine, cosmetics, plastics and paints

34. Hematite
Iron Oxide
Fe O