Chapter 2 Minerals

Chap 2.1 Matter Element: A substance that can’t be chemically or physically broken down into simpler substances The element Hydrogen

Atom: Parts of atom: Nucleus: The smallest particle of matter Have all the characteristics of an element Parts of atom: Nucleus: The center of an atom, most of the mass is the nucleus

In the nucleus: Protons: Neutrons: Have a positive charge, jammed tightly together, every atom of the same element ALWAYS has the same number of protons Neutrons: Have no charge, jammed together with protons, atoms of the same element doesn’t always have the same number of neutrons

Energy levels, or shells Outside of the Nucleus Electrons: Have a negative charge, very small, found in orbitals (layers or energy levels) outside the nucleus Energy levels, or shells Surround the nucleus Contain electrons—negatively charged particles

When atoms combine or interact, it’s always the electrons that do the interacting

Review

Words to Know Atomic number: The number of protons in the nucleus Atomic mass: The number of protons + neutrons in an atom

Isotopes: Atoms with the same number of protons (same element) but different numbers of neutrons

Ion: An atom or molecule that gains or loses an electron, ions have charges A CHARGED PARTICLE!

3 types of bonds between atoms Chemical Bonds Ways that electrons are used in making bonds between atoms or molecules 3 types of bonds between atoms 1. Ionic: Bonds formed between ions, where electron is transferred from one atom to another, the strongest chemical bond, like in salt

Bonds between different molecules: Hydrogen bonds: Covalent: Electrons are shared between atoms (not always shared equally), like between atoms in a water molecule H2O Metallic: Many electrons are shared by many metal ions, like in copper, iron, etc Bonds between different molecules: Hydrogen bonds: Weak bonds between polar molecules, like water because electrons not shared evenly

Questions If opposites attract and same charges repel, why are the protons so close together in the nucleus and the electrons are outside the nucleus? The Strong Force (1039 times stronger than gravity) keeps protons held together even though the electromagnetic force tries to separate them. What about the electrons? The closer they get to nucleus, faster they go

Chap 2.2 Minerals Mineral: Naturally occurring, not made by man Inorganic, (generally not made by living organisms) Solid Orderly crystalline structure (atoms are arranged in orderly, repetitive way) Definite chemical composition (all minerals of the same type have very similar composition)

Mineral Formation Minerals generally form in 1 of 4 ways: Crystallization of magma: Crystals grow as magma cools, slow cooling makes large crystals because they grow slowly Precipitation: As water cools or evaporates, minerals precipitate (settle) to the bottom Pressure & Temperature: Minerals can change type under high pressure or temperatures, like metamorphic rocks change

Hydrothermal Solutions: Very hot water with dissolved minerals can cause some minerals to dissolve and form new minerals or combine to form other minerals

Chap 2.3 Mineral Properties Color: Not a very good way to determine mineral because small amounts of impurities can change the color

Streak: The color of the powder left from scratching a mineral on a streak plate, this is a good way to determine type of mineral Luster: The way light is reflected from the surface, like shiny, dull, pearly, etc

Crystal Form: The 3 dimensional shape of a crystal as it grows with plenty of space and time Hardness: Resistance to being scratched, ranked on the Mohs scale from 1 – 10, with 10 being hardest. Fingernail = 2.5, Glass = 5.5, Diamond = 10

Cleavage: Ability of mineral to break leaving smooth, flat surfaces, like mica or salt Fracture: Breaking without leaving a smooth, flat surface, like quartz Density: Mass / Volume