2.1 – Matter 2.2 – Minerals 2.3 – Properties of Minerals Chapter 2: Minerals 2.1 – Matter 2.2 – Minerals 2.3 – Properties of Minerals

2.1 Matter What is an element? What particles make up atoms? What are isotopes? What are compounds and why do they form? How do chemical bonds differ?

Show what you know! Work with a partner Discuss what you already know about atoms Draw a picture of an atom based on what you and your partner know Include as many details as possible!

Periodic Table of the Elements What is an element? An element is a substance that cannot be broken down into simpler substances by chemical or physical means Elements are the basic building blocks of minerals (and everything else!) The 3 basic types of elements are metals, nonmetals, and metalloids Periodic Table of the Elements

What is an element? Elements are organized by their properties on the periodic table What is the universe made of? - Dennis Wildfogel Atomic number Element symbol Element Name Atomic mass

Most Common Elements in Earth’s Continental Crust What is an element? Most Common Elements in Earth’s Continental Crust Element % by Weight Oxygen (O) 46.6 Silicon (Si) 27.7 Aluminum (Al) 8.1 Iron (Fe) 5.0 Calcium (Ca) 3.6 Sodium (Na) 2.8 Potassium (K) 2.6 Magnesium (Mg) 2.1 Others 1.7

What particles make up atoms? Nucleus Protons – positively charged particles Neutrons – neutral particles Electron Cloud Electrons – negatively charged particles

What particles make up atoms? The identity of an atom is determined by it’s number of protons, or atomic number. The atomic mass of an atom is equal to the number of protons plus the number of neutrons The electrons in an atom are involved in chemical bonds with other atoms

What are Isotopes? Video: How Does Radiocarbon Dating Work? Atoms with the same number of protons but different numbers of neutrons are isotopes of an element Isotopes have a different mass number than other versions of the same element

What are Isotopes? An atom that creates isotopes easily is known as unstable Unstable atomic nuclei disintegrate in a process called radioactive decay The rate of this decay is measurable so radioactive elements can be used to determine the age of fossils, rocks, and minerals

What are compounds and why do they form? A compound is a substance that consists of two or more elements that combine in specific proportions

What are compounds and why do they form? Atoms form compounds in order to become more stable Video - Sodium in Water + 

What are compounds and why do they form?

What are compounds and why do they form?

What are compounds and why do they form?

Ionic Bonds Covalent Bonds Metallic Bonds Ions form when an atom gains or loses electrons and becomes charged ( + or -) Ionic bonds form between positive and negative ions Rigid solids with high melting and boiling points Conduct electricity when melted or dissolved in water Examples: NaCl (table salt) CaCl (chalk) Covalent bonds form when atoms share electrons Have low boiling and melting points do not conduct electricity Examples: H2O (water) SiO2 (quartz) Metallic bonds form when atoms are shared between metallic ions Malleable & ductile – can be bent or drawn into wires Conduct electricity Examples: Cu (copper) Fe3C (steel)

2.2 Minerals What are five characteristics of a mineral? What processes result in the formation of minerals? How can minerals be classified? What are the major groups of minerals?

A mineral is a naturally occurring, inorganic solid with an orderly crystalline structure and a definite chemical composition. Naturally occurring- forms from geologic processes Solid substance- hard at normal temperatures Orderly crystalline structure- atoms are arranged in orderly repetitions Definite chemical composition – made of the same elements for any sample. Generally considered inorganic- not from living things

How do minerals form? Crystallization from magma- elements combine in an orderly structure when magma cools underground Precipitation- minerals fall out of solution because the water evaporates or changes temperature Pressure and temperature- minerals can change form when heated or compacted Hydrothermal solutions- very hot water with dissolved substances can form new minerals

How can minerals be classified? Minerals are classified into groups based on their chemical composition Common mineral groups include: silicates, carbonates, oxides, sufates and sulfides, halides, and native elements.

Silicates The silicon-oxygen tetrahedron forms the framework of every silicate mineral. 90% of Earth’s crust is composed of silicate minerals Sand, glass, bricks, stones, soil, concrete, quartz Piezoelectric effect – quartz produces an electric charge when compressed, bent or twisted (watches & radio receivers)

Silicates Opal Olivine Garnet Amethyst

Carbonates Carbonates contain CO3 ions Aragonite Cave in Slovakia

Calcite was used for gun sights in WWII because it is fluorescent under UV light Carbonates

Oxides Contain oxygen and metal ions Uranium Ore Oxides Contain oxygen and metal ions Bauxite (aluminum ore): requires a lot of energy to process into aluminum which is why aluminum is commonly recycled Iron Ore Aluminum Ore Tin Ore Copper Ore

Sulfates and Sulfides Contain the element sulfur The mineral gypsum is used in drywall and plaster of paris

Crystal Cave, Naica Mexico

Halides Contain halogens (group 7 on the periodic table) Fluorite is a source of fluoride which is used in toothpaste Halite is the mineral name for table salt

Native Elements Native elements are minerals that contain only one type of element (only one type of atom)

2.3 Properties of Minerals What properties can be used to identify minerals? What is the Moh’s Scale? What are some distinctive properties of minerals? Mineral properties depend on the elements that compose the mineral and it’s structure

What properties can be used to identify minerals? Color Not actually very useful Small amounts of different elements can give the same mineral different colors

What properties can be used to identify minerals? Streak Streak is the color of the mineral in powdered form. Find streak by rubbing a mineral against a streak plate Galena Sulfur Pyrite Calcite Olivine Lodestone Observation – Observation -

What properties can be used to identify minerals? Luster Describes how light is reflected from the surface of a mineral Obsidian Galena Gypsum Hematite Glassy luster Metallic luster Silky luster Earthy luster

What properties can be used to identify minerals? Crystal form Visible expression of a mineral’s internal arrangement of atoms

Bismuth Crystal Structure (lab grown)

What properties can be used to identify minerals? What is the Moh’s scale? Hardness The Moh’s scale is a standard scale used to compare the hardness of minerals

What is the Moh’s scale? Mineral Mini-Lab You will be given a mineral to test for hardness using various objects of known hardness. To test your mineral, rub the mineral against the object and check for scratches. If a mineral scratches an object, the mineral is harder than the object. If an object scratches a mineral, the mineral is softer than the object. Answer the questions for each object used to test your mineral. As a class, rank each item from hardest to softest

What is the Moh’s scale? Mineral # ____ Is your mineral harder than a fingernail? Is your mineral harder than a copper penny? Is your mineral harder than a wire nail? Is your mineral harder than a piece of glass?

What is the Moh’s scale?

What properties can be used to identify minerals? Cleavage The tendency of a mineral to cleave, or break along flat, even surfaces Crystal structure of mica

What properties can be used to identify minerals? Fracture Fracture is the uneven breakage of a mineral Minerals show either cleavage or fracture

What properties can be used to identify minerals? Density The density of a pure mineral is a constant value. Density can be used to determine the purity or identity of some minerals How taking a bath led to Archimedes' principle - Mark Salata

What are some distinctive properties of minerals? Some minerals can be recognized by other distinctive properties Talc Magnetite Sulfur Calcite Graphite Feels soapy magnetic Smells like rotten eggs Fizzes when dropped with HCl Feels greasy