Chapter 3 Atoms to Minerals BFRB P

Matter MASSVOLUMEDef. anything that has MASS and VOLUME –Mass is the amount of material in an object (it is often referred to as weight, but this is incorrect! In order to have weight, you need gravity, but you don’t need gravity for MASS) –Example – An astronaut in space has no weight, but has mass! This guy on the Moon weighs only 1/6 th of his weight on Earth, but his MASS is still the same!!!!

Elements & Atoms All matter is made up of elements Def. An element is a substance that cannot be broken down into a simpler substance –Ex: oxygen or gold Elements are made up of atoms Def. An atom is the smallest part of an element that still has the characteristics of that element

Parts of an Atom Protons Protons (+ positive charge) Neutrons Neutrons (neutral no charge) NUCLEUS –Both found in the NUCLEUS Electrons Electrons (- negative charge) spin around the nucleus

Periodic Table of Elements

Your Periodic Tables are found in the textbook, pages ! ATOMIC NUMBERATOMIC NUMBER – number of protons (found at the top/center of box) ATOMIC MASSATOMIC MASS – number of protons plus neutrons (found at the bottom/center of box)

Isotopes All elements that are the same element have the same atomic #All elements that are the same element have the same atomic # –Ex: all carbon atoms have 6 protons (atomic # 6) Elements that are the same but have a different Mass # are called ISOTOPESThis is NOT true for the # of Neutrons! Elements that are the same but have a different Mass # are called ISOTOPES –Ex: Carbon-12 has 6 protons and 6 neutrons (6+6=12), while Carbon-14 has 6 protons and 8 neutrons (6+8=14)

Compounds Def. Substance made of 2 or more elementsDef. Substance made of 2 or more elements Elements are Chemically bonded together (you’ll learn about this in chemistry)Elements are Chemically bonded together (you’ll learn about this in chemistry) A Molecule is the smallest part of a compoundA Molecule is the smallest part of a compound –Ex: water is a compound of 2 Hydrogens and 1 Oxygen H 2 O) Hydrogen Atoms Oxygen Atom Looks like Mickey Mouse, doesn’t it?

Chemical Bonds Atoms carry their electrons in “shells” that surround the nucleus.Atoms carry their electrons in “shells” that surround the nucleus. Each shell can hold a certain # of electronsEach shell can hold a certain # of electrons Shell 1 can hold 2 electrons.Shell 1 can hold 2 electrons. Shell 2 can hold 8 electronsShell 2 can hold 8 electrons Shell 3 can hold 18 electrons.Shell 3 can hold 18 electrons. An atom’s goal in life is to have a full outer shell so it can be as stable as possible.An atom’s goal in life is to have a full outer shell so it can be as stable as possible. It will give up, gain, or share its electrons to achieve this goal.It will give up, gain, or share its electrons to achieve this goal.

Chemical Bonds The electrons in the outermost energy level of the atom are called valence electrons.The electrons in the outermost energy level of the atom are called valence electrons. When the outermost energy level is full, the atom is stable and won’t form chemical bonds. These are the “noble gases” on the far right hand side of the periodic table.When the outermost energy level is full, the atom is stable and won’t form chemical bonds. These are the “noble gases” on the far right hand side of the periodic table. The elements on the left hand side have 1,2,3 or 4 extra electrons that they want to give up – these are the metals.The elements on the left hand side have 1,2,3 or 4 extra electrons that they want to give up – these are the metals. The elements on the right side have 4,5,6 or 7 electrons and they want more – these are the non-metals.The elements on the right side have 4,5,6 or 7 electrons and they want more – these are the non-metals.

Compounds Ionic bonds – When one atom loses its outer electron and another atom gains it. Common between a metal and nonmetal.Ionic bonds – When one atom loses its outer electron and another atom gains it. Common between a metal and nonmetal. Ex – a sodium atom (metal) has one electron in its outer shell and a chloride (nonmetal) atom needs one electron in its outer shell.Ex – a sodium atom (metal) has one electron in its outer shell and a chloride (nonmetal) atom needs one electron in its outer shell. So, the sodium atom “gives” its electron to the chloride atom and they are both more stable now because their outer shells are full.So, the sodium atom “gives” its electron to the chloride atom and they are both more stable now because their outer shells are full. The 2 atoms now have opposite charges – the sodium is positive and the chloride is negative – since opposites attract – they BOND together.The 2 atoms now have opposite charges – the sodium is positive and the chloride is negative – since opposites attract – they BOND together.

Compounds Covalent bonds – When two atoms combine and share electrons. Common between 2 nonmetals.Covalent bonds – When two atoms combine and share electrons. Common between 2 nonmetals. Ex – one oxygen atom and two hydrogen atoms get together and share eight electrons so all of their outer shells are full.Ex – one oxygen atom and two hydrogen atoms get together and share eight electrons so all of their outer shells are full. The first valence shell holds 2 atoms (Hydrogens) and the second valence shell holds 8 atoms (Oxygen).The first valence shell holds 2 atoms (Hydrogens) and the second valence shell holds 8 atoms (Oxygen).

What does all this have to do with Minerals? Minerals may form via Ionic Bonds or Covalent Bonds.Minerals may form via Ionic Bonds or Covalent Bonds. Some minerals are not compounds formed by 2 or more elements – they are just one element on its own – these are known as “native elements”.Some minerals are not compounds formed by 2 or more elements – they are just one element on its own – these are known as “native elements”. –Examples are gold, silver, copper, sulfur, diamond, platinum, etc.

To sum up… the order of matter, from smallest piece to largest is… Compound Elements MoleculesAtoms Protons, Neutrons and Electrons make up of different elements make up are the smallest part of a of the same kind make up 2 or more elements make up a

Mineral Criteria The 5 “must haves” for a substance to be classified a MINERAL

1. Naturally Occurring A mineral cannot be man-made!!! It must be formed in nature by one of two ways: Solidification 1. Solidification of molten materials Evaporation 2. Evaporation of seawater

2. Solid Matter MUST BE A SOLIDA mineral MUST BE A SOLID! a powder is still a solid –Minerals can be crushed into powder – but remember – a powder is still a solid! –There are NO liquid or gaseous minerals naturally occurring!

3. Definite Chemical Composition Elements combine in exact proportions ex: Halite is a compound of Na (Sodium) and Cl (Chlorine) – this is the same as table SALT! LOOK AT YOUR REFERENCE TABLES P. 16! Each mineral has a definite chemical composition – a “Recipe” for making that mineral. Change the recipe and you change the mineral!

4. Atoms Arranged in an Orderly Pattern PATTERNThis means that when the atoms combine, they must form a PATTERN CRYSTALLINE structure –This pattern is called a CRYSTALLINE structure Crystals –Some minerals actually form “Crystals” The shape of the crystal patterns affect the hardness and the shape of the mineral!

5. INORGANIC This means that the chemical composition of the mineral CANNOT have a Carbon-Hydrogen bond in it. Ex Calcium Carbonate - CaCO 3 Does it contain Carbon? YES! Does it contain a Carbon-Hydrogen bond? NO!

To sum up….. Key Ideas

The 5 Criteria for a Substance to be Called a Mineral 1. Must occur naturally 2. Must be a solid 3. Must have a definite composition 4. Atoms must be in a pattern 5. Must be inorganic

Silica Tetrahedron Most minerals are composed of only 8 of the 109 known elements! OXYGEN & SILICONThe 2 most abundant elements that they are made of are OXYGEN & SILICON (they are found found in 90% of them) SILICATES –These minerals (90%) are called SILICATES –They are made of a basic unit of SiO 4 – 1 Silicon surrounded by 4 Oxygens in a “pyramid”-like pattern!