Elements, Minerals, Rocks, Soil, Agriculture Unit 3: Geosphere Part 2 Elements, Minerals, Rocks, Soil, Agriculture

What are Atoms? Are made up of chemical elements. Each element has nearly identical atoms. Atoms have three different particles: - protons (+) located in center of atom -electrons (-) located around center of atom -neutrons (0) located in center of atom

What is an Element? Elements have the same # of protons and electrons Number of protons = number of electrons Isotopes of an element have the same number of protons and electrons, but they have a different number of neutrons. Many isotopes are radioactive and emit energy and particles.

What do Atoms look like? Have energy levels, or shells: The shells surround the nucleus (center of atom) Contains electrons- negatively charged particles

Why do Atoms form bonds? When an atom’s does not contain a full outer shell, it is likely to form a chemical bond with one or more atoms. A compound: consist of two or more elements that are chemically combined in specific proportions.

Types of Chemical Bonds 1. Ionic bonds: form between metal and nonmetal 2. Covalent bonds: form between two non-metals. 3. Metallic bonds: form between two metals.

the Periodic Table

Practice: Is it a metal, non-metal, metalloid? Na N Metal Li H

What is a mixture? Mixture is any combination of two or more substance that are not chemically combined. Examples of mixtures: Salt & pepper _______________________ Sweet tea

Organic Vs. Inorganic Organic: Made of Carbon and hydrogen Normally living organisms or products of living organisms Inorganic: Made of everything else Normally non-living or man made

Minerals Mineral: a naturally occurring, inorganic crystalline material with a unique chemical composition. http://www.feenixx.com/earth-science/Introduction_to_Minerals_Poster.htm

Minerals Characteristics: Naturally formed- it forms in nature on its own Orderly crystalline structure Solid (cannot be liquid or gas) Has to have a definite chemical composition Has to have a characteristic crystalline structure

What makes a Mineral different? Mineral characteristics are determined by the arrangement of atoms Diamond & Graphite have the same chemical composition, but a different atom arrangement.

What makes a Minerals different?

Examples of Minerals: Glass- can be naturally formed (volcanic glass is called obsidian) Ice- is naturally formed, is a solid, has definite chemical composition Halite (salt)- naturally formed, is solid, has definite crystalline structure.

Characteristics of Minerals Color Streak Luster Crystal form Hardness Cleavage Fracture Density

Characteristic of Minerals- Color Small amounts of different elements can give the same mineral different colors.

Characteristic of Minerals- Color Is a poor mineral indicator Minerals can be multiple colors Many minerals are the same color Quartz

Characteristic of Minerals- Streak Streak: is the color of a mineral in its powdered form. More reliable than color

Characteristic of Minerals- Luster Luster: is used to describe how light is reflected from the surface of a mineral.

Characteristic of Minerals- Luster Non-metallic Looks waxy, greasy or brilliant Leaves white or no streak on a black streak plate Metallic Looks like metal Leaves a dark streak (black, grey, green, or brown) on a white streak plate

Characteristic of Minerals- Crystal Form Crystal form: is the visible expression of a mineral’s internal arrangement of atoms.

Characteristic of Minerals- Hardness Hardness: is a measure of the resistance of a mineral to being scratched. Mohs scale: consists of 10 minerals arranged from 10 (hardest) to 1 (softest)

Characteristic of Minerals- Cleavage Cleavage: is the tendency of a mineral to cleave, or break, along flat, even surfaces. At least one distinct flat side when broken

Characteristic of Minerals- Fracture Minerals that do not show cleavage when broken are said to fracture. Fracture: the uneven breakage of a mineral

Characteristic of Minerals- Density Density: is a property of all matter that is the ratio of an object’s mass to its volume.

Important All minerals are rocks!!! Not all rocks are minerals nor are they composed of minerals!!! Example: Coal is a rock and it is organic

What is a Rock? Rocks are any solid mass of mineral or mineral-like matter occurring naturally as part of our planet. Types of Rocks Igneous Metamorphic Sedimentary

What is an igneous Rock? Igneous rocks Created from cooling of melted rock called magma As the magma cools it crystallizes

Igneous Rocks-Characteristics Most igneous rocks are very hard Made of crystals Layering is not common in igneous rocks

Intrusive vs. Extrusive Igneous Rocks Intrusive igneous rocks from when magma cools slowly under the Earth’s surface. Large crystals Extrusive igneous rocks from when the magma cools quickly on the Earth’s surface. Very small crystals

What is a metamorphic rock? Formed when buried rock is changed under high temperature and pressure Rock doesn’t melt. Instead, new minerals grow and the rock remains solid. Gneiss

Metamorphic Rocks – Characteristics Layering is common in metamorphic rocks Different layers are made up of different minerals Often made of plates and flaky layers

Foliated vs. Nonfoliated Metamorphic rocks Foliated metamorphic rocks has a banded or layered appearance Nonfoliated metamorphic rocks does not have a banded texture