WARM-UP #11 JAN. 25Atomic Theory

States that matter is composed of discrete units called atoms

The word "atom" comes from the ancient Greek adjective atomos meaning 'indivisible’

Essential Question:When and where do you think mankind

originally began to ponder as to what makes up the elements and atoms?

SUBATOMIC PARTICLESName Symbol Charge Relative

Actualmass mass

Electron e- -1 1/1840 9.11 x 10-28

Proton p+ +1 1 1.67 x 10-24

Neutron n0 0 1 1.67 x 10-24

crap

SYMBOLS The symbol of an element contains the mass

number and the atomic number:

XMass Number

Atomic Number

SYMBOLSFind the:1. Number of Protons2. Number of Neutrons3. Number of Electrons4. Atomic Number5. Mass Number Rh104

45

Rhodium - 104

HISTORY OF THE ATOM The original idea of the atom came from

Ancient Greece (400 B.C.) Democritus – Greek Philosopher He and his mentor Leucippus

first described that all things weremade up of “atoms”

WHO’S NEXT? Late 1700’s – John Dalton – England Teacher – summarized results of his

experiments and those of others in his Atomic Theory.

His idea combined ideas of elements with atoms

DALTON’S ATOMIC THEORY All matter is made up of tiny individual

particles called atoms Atoms of the same element are identical,

those of different elements are different Atoms of different elements combine in

whole number ratios to form compounds Chemical reactions involve the

rearrangement of atoms. No new atoms are created or destroyed.

JJ THOMSON J.J. Thomson – English physicist, 1897 Made a piece of equipment that explored the

properties of cathode rays. Basically discovered that atoms of divisible

THOMSON’S MODEL Found the electron Couldn’t find positive (for a while) Said the atom was like plum pudding A bunch of positive stuff, with the electrons

able to be removed

PROTONS Proton – positively charged pieces

1840 times heavier than the electron. Eugene Goldstein used a modified

cathode ray Rutherford predicted its presence in

the atom with gold foil experiment

RUTHERFORD’S EXPERIMENT Ernest Rutherford was an English Physicist

(1910) Believed in the plum pudding model of the

atom. Wanted to see how big they are Used radioactivity Alpha particles – positively charged pieces

given off by uranium Shot them at gold foil which can be made a

few atoms thick

HE EXPECTED The alpha particles to pass through without

changing direction very much. Because…

The positive charges were spread out evenly.Alone they were not enough to stop the alpha particles

WHAT HE GOT

HOW HE EXPLAINED IT Atom is mostly empty Small dense, positive Piece at center Alpha particle are deflected by it if they get

close enough

DENSITY OF THE ATOM Since most of the particles went through, it

was mostly empty Because the pieces turned so much, the

positive pieces were heavy Small volume, big mass, big density. This small dense positive area is the nucleus

BOHR’S MODEL – 1915 Why don’t the electrons fall into the nucleus? Move like planets around the sun. In circular orbits at different levels Amounts of energy separate one level from

another

BOHR’S MODEL The further an electron is from the nucleus

the more energy it has There is no “in between” energy It is like a ladder

BOHR’S IS NOT RIGHT EITHER! Bohr got closer than we had been so far, but

it was still not right. He gave us the idea of energy levels for

electrons. BUT his idea only worked for one atom

NEUTRONS No charge Same mass as the

proton Discovered by James

Chadwick during radioactivity experiments in 1932

QUANTUM MECHANICAL MODEL 1925 - Erwin Schrondinger used the results of

the experiments done with the hydrogen atom to come up with the quantum mechanical model

This comes from a mathematical solution to the Schrodinger equation

The quantum mechanical model determines the allowed energies an electron can have and how likely it is to find the electron in various locations.

QMM Has energy levels for electrons Orbits are not circular It can only tell us the probability of finding an

electron a certain distance from the nucleus.

MODERN VIEW The atom is mostly empty space Two regions Nucleus – protons and neutrons Electron cloud – region where you might find

an electron

ATOMIC THEORY TIMELINE ASSIGNMENT You are to create a timeline that maps out each

significant event throughout history that involves the atomic theory.

There will be at least 8 events (all were covered in the notes)

For each event I want the: Date Person What they contributed (IN COMPLETE SENTENCES). A drawing or something of what they discovered.

They need to be colored.

TICKET OUT THE DOOR1. What does the atomic number tell

you about an element?2. What are the three subatomic

particles, their relative masses, relative charges, and location(which region of the atom)?

3. What is a compound?4. What is an isotope?

WARM-UP #12 JAN. 26

Cations When an element

becomes positively charged it forms a cation

Anion When an element

becomes negatively charged it forms an anion

An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons

What do you have to lose in order to become positively charged?

THE PERIODIC TABLE The periodic table is based on the Modern

Periodic Law Came from the QMM Set up in rows called periods

Indicate the main energy level Columns called groups or families

Similar properties

Dmitri Mendeleev was one of the first scientists to realize there was a trend in the properties of the elements

CLASSIFYING We separate the periodic table several ways

to help classify the elements This includes dividing it by families, and type

of element

Representative – group A Transitions – group B

We split the table into these 2 major groups Most of what we deal with deal with is in group A

or the representative elements

METAL ~ NONMETAL ~ METALLOID These are three of our other main

classifications Elements that fit into these groups have

specific properties

METALS Most metals are solid at room temperature

Which one is the exception? Mercury – Hg

Generally good conductors of heat and electric current Sea of free floating electrons

Usually form cations Usually malleable and ductile

NONMETAL Less similarities in the nonmetals Typically poor conductors of heat and electric

current Solid nonmetals tend to be brittle

Carbon, Sulphur

METALLOID These elements have properties that are

similar to both metals and nonmetals Semiconductors

Can be used to produce superconductors Boron, silicon, arsenic

PERIODIC TABLE ASSIGNMENT Pick 3 elements, one from each subgroup

(metal, nonmetal, metalloid) Research each element:

Draw the symbol as you would see it on the periodic table

Label the atomic number and mass number Tell me where the element is found and how we

use it Products, industry, etc.

Describe some of its properties Draw a picture of what it looks like naturally These should be colored

WARM-UP #13 JAN. 27 Valence Electrons - are the electrons of an

atom that can participate in the formation of chemical bonds with other atoms.

Electron dot diagrams - diagrams that show the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule

HOW DO ELEMENTS FORM IONS AND WHY? All elements are trying to get the same

number of electrons as the nearest noble gas Far column on the right

This is where valence electrons come in

VALENCE ELECTRONS All atoms have valence electrons These are the electrons responsible for

forming bonds They are the furthest from the nucleus They fill the outermost energy level These determine the properties of the atom,

such as stability.

Every element can only have 8 valence electrons

They WANT to have 8 like the noble gases

Helium only has 2 electrons TOTAL, so some elements are content

VALENCE ELECTRONS You can determine how many valence

electrons for Group A by looking at the groups number

VALENCE ELECTRONS We represent valence electrons using

electron dot diagrams.

Electron dot diagrams show the element symbol with dots representing the valence electrons

BOHR’S MODELShows ALL of the element’s

electrons

1st – 2e-

2nd – 8e-

3rd – 18e-

4th – 32e-

NITROGEN

N

ALUMINUM

Al

IONSAtoms form ions based on the number of valence electrons

Group VIII A8 valence electrons (8 ve-)

What is the charge as an ion?0

Positive ions are called cationsThese are formed when an atom

loses electronsThe metals usually form cations

Negative ions are called anionsThese are formed when an atom

gains electronsThe nonmetals usually form anions

When an atoms forms an ion it changes size because it becomes stableCations are much smaller the

atom in which they formAnions are much bigger than

the atom from which they form

TICKET OUT THE DOOR1. What does the atomic number tell

you about an element?2. What are the three subatomic

particles, their relative masses, relative charges, and location(which region of the atom)?

3. What is a compound?4. What is an isotope?

PRACTICE Draw e- dot diagram, bohr model

diagram, and tell what charge each will have as an ionSodiumSulfurSiliconOxygenArgonChlorineBeryllium

WARM-UP #14JAN. 30

Draw e- dot diagram, bohr model diagram, and tell what charge each will have as an ion:FluorineNeonCarbon

REVIEW What are your three subgroups of

elements on the periodic table?MetalsNon-metalsMetalloids

What is an isotope?Atoms that have the same number of

protons but different number of neutrons.

REVIEW What the atomic number equal to?

Number of protons

What is the mass number equal to? Number of protons and neutrons

What is a valence electron? Electron found on the out shell of an atom.

There can only be 8 total.

TYPES OF CHEMICAL BONDS Ionic Bonds

Form between positive and negative ions Ex: salt forms when sodium reacts with chlorine

Covalent Bonds Form when atoms share electrons Ex: Silicon dioxide forms when one silicon atom

and two oxygen atoms share electrons in that outermost energy level

Metallic Bonds Form when electrons are shared by metal ions

MINERALS A mineral is a naturally occurring, inorganic

solid with an orderly crystalline structure and definite chemical composition.

There are nearly 4000 known minerals

NATURALLY OCCURRING A mineral forms by natural geologic

processes. Synthetic gems are not minerals

SOLID SUBSTANCE Minerals are solids within the temperature

ranges that are normal for Earth’s surface Definite shape Definite volume

ORDERLY CRYSTALLINE STRUCTURE Their atoms or ions are arranged in an

orderly and repetitive manner

DEFINITE CHEMICAL COMPOSITION Every mineral is made up of a specific

compound. Each sample of that mineral is made of the same compound.

Different minerals are different compounds Ex: Quartz – Si02

GENERALLY CONSIDERED INORGANICWhat do you think it means to be

organic?Organic means that it is a compound

containing carbonMost minerals do not contain

carbon We say generally because there are

some animals that secrete compounds considered mineralsEx: Calcite : calium carbonite

SOURCEhttp://www.rocksandminerals.com/uses.htm

TICKET OUR THE DOOR1. What is a mineral?2. Give me two characteristics a mineral must

have.3. Give an example of a mineral and one of its

uses.4. Draw an e- dot diagram and Bohr model for

Phosphorus1. LOCATED IN GROUP 5A

WARM-UP #15JAN. 31What are five

characteristics of a mineral?

Coal forms from ancient plant matter that has been compressed over time. Do you think coal is a mineral?

HOW MINERALS FORMThere are four major processes by

which minerals form:Crystallization from magmaPrecipitationChanges in pressure and

temperatureFormation from hydrothermal

solutions

CRYSTALLIZATION FROM MAGMA Magma is molten rock As magma cools, elements

combine to form minerals First minerals are usually rich in

iron, calcium, and magnesium. As minerals continue to form

the magma changes composition forming minerals rich in sodium, potassium, and aluminum

PRECIPITATION Water contains dissolved substances As the water evaporates some of the

dissolved substances can react to form minerals.

Limestone and Halite are common examples of precipitation

PRESSURE AND TEMPERATURE Some minerals form when existing minerals

are subjected to changes in pressure and temperature

An increase in pressure can cause a mineral to recrystallize while still solid

Atoms are rearranged Temperature change can cause minerals to

become unstable and form new minerals that are stable at the new temperature.

HYDROTHERMAL SOLUTIONS 100° C – 300° C Very hot mixture of water and dissolved

substances When they come into contact with existing

minerals, chemical reactions take place and form new minerals

Minerals can also form when these solutions cool

MINERAL GROUPS There are 6 groups of minerals that we will

discuss Silicates Carbonates Oxides Sulfates/Sulfides Halides Native Elements

SILICATES Most common Contain silicon-oxygen tetrahedron Groups based upon tetrahedron arrangement

Olivine Pyroxene Amphibole Micas Feldspars Quartz

OLIVINE Independent tetrahedron

PYROXENE GROUP Tetrahedrons are arranged in chains

AMPHIBOLE GROUP Tetrahedron are arranged in double chains

MICAS Tetrahedron are arranged in sheets Two types

Biotite – dark Muscovite - light

FELDSPARS Three-dimensional network of tetrahedron Two types:

Orthoclase Plagioclase

QUARTZ Three dimensional network of tetrahedron

CARBONATES A major rock-forming group Found in the rocks limestone and marble Calcite and Dolomite are carbonate minerals

OXIDES Minerals that contain oxygen and one or

more other elements. Rutile – TiO2 form as magma cool Corundum – Al2O3 forms when existing

minerals are subjected to changes in temperature and pressure

SULFATES AND SULFIDES Minerals that contain sulfur

Anhydrite – CaSO4 Gypsum Pyrite – fools gold

HALIDES Minerals that contain a halogen Salts Halite – table salt Fluorite

NATIVE ELEMENTS Group of minerals that exist in relatively pure

form Gold Silver Copper Sulfur Diamond Graphite

WARM-UP #16FEB. 1

Think of and list as many properties as you can that help us identity minerals. Again, these are different than the characteristics of minerals.

Why is it important to identify minerals?

MINERAL PROPERTIES Minerals are classified by a set of specific

properties

These are considered intensive properties This means they don’t depend on the amount of

the substance, but the composition instead

COLOR Color is the first thing you will notice about a

mineral Do you think this is a good indicator of what

a mineral is made of? Not always A very small difference in amount of

elements present can change the color of the mineral

LUSTER Luster describes how light is reflected off the

surface of a mineral Minerals that have the appearance of metals

are said to be metallic. Nonmetallic luster is described in many

different ways: Vitreous Glassy Pearly Silky Earthy Adamantine Sub-metallic

STREAK Streak is the color of a mineral in its

powdered form. You can obtain this by rubbing a mineral

across a streak plate (unglazed porcelain) Streak does not usually vary even if the color

does

CRYSTAL FORM Visible expression of the internal

arrangement of atoms

HARDNESSA measure of the resistance of a

mineral to being scratched

One of the most useful properties in identifying minerals

We use the Mohs scale of hardness

CLEAVAGE AND FRACTURE

Cleavage and fracture both deal with how a mineral breaks apart

Cleavage is the tendency to break along a flat even surfaces

Fracture is the uneven breakage of minerals

Mica shows cleavage; breaking in even flat sheets

FRACTURE

DENSITY Density is a property of all matter that is the

ratio of an object’s mass to its volume. Think of it as how compact the substance is

Grams

Cubic centimeters or milliliters

PRACTICEA 6.75 g solid with a volume of 5.35 cm3. Find the density.

D = 6.75g / 5.35 cm3

D = 1.26 g/cm3

OTHER PROPERTIESSome minerals have distinctive feelsTalc is soapy, and graphite feels

greasySome minerals are magnetic like

magnetiteSome have distinctive smells

like sulfurCalcite reacts chemically with

hydrochloric acid and will fizz

REFLECTION In your journals, tell me what you did today

and how it is important. Describe the different properties of minerals

and how you used them today to determine the identity of various minerals.

What were some properties of specific minerals that gave their identity away relatively easily.

WARM-UP #17 FEB. 2 What are the differences between ionic

bonds, covalent bonds, and metallic bonds? (use your notes)

What are halogens?

TICKET OUT THE DOOR Name 4 properties of minerals used for

identification. How do we calculate density? What is the difference between cleavage and

fracture?