The Structure of the Atom On page 22 of your ISN, don’t forget to add to your TOC!

The Structure of the Atom The atom is the smallest part of an element, while still maintaining it’s properties. “indivisible”“can not be divided”

Draw an atom

Nucleus- tiny dense cluster of protons and neutrons in the center of the atom Protons-has a positive (+) charge. The # of protons determines the atomic number Neutron- are neutral (No charge). The # of neutrons+ the # of protons= Atomic mass Electrons- have a negative (-) charge. They are in rapid, continuous motion around the nuclues Electron cloud- surrounds the nucleus and contains the electrons. “empty space”

Out put-Analogy of an Atom Use Bohrs model and write an analogy comparing the structure of an atom to the solar system.

Digging deeper with atoms Page 24 of your ISN, don’t forget the TOC!

Electrons Electrons circle the nucleus in an electron cloud. The outermost electrons are called valence electrons. Each level/shell can only handle so many electrons until it is full and has to send electrons to another level/shell.  Level one- 2 electrons  Level two- 8 electrons  Level three- 18 electrons  Level four- 32 electrons

Isotopes Atoms that can have a wide range of number of neutrons in the nucleus. Different types, have different uses

Atomic Number Number of protons in the nucleus of each atom of a given element Mass Number Number of protons + number of Neutrons

Time to practice- * Output side Please draw an atom that has 5 protons, 6 neutrons, and 5 electrons. Include their charges and correct locations. (using color!) What is the atomic number for this atom? What is the atomic mass for this atom?

Time to practice #2 Please draw the following pair of isotopes. Identify the atomic mass and mass number for each(Use color!) N N

Periodic Table Page 26 of your ISN, be sure to include in your TOC!

Element Matter made up of only one kind of atom Takes up space and has mass*

Mendeleev Arranged 63 known elements Based on chemical properties and atomic weight Left gaps for elements he predicted were yet to be discovered

C6Carbon Atomic Number- Number of protons in the nucleus Element Name Symbol Atomic Mass Average weight of element isotopes

Physical Properties of metals, nonmetals and metalloids * output

Metals Shiny/metallic luster Solid at room temperature (except Mercury) Reflect light when polished (luster) Can bent or hammered flat(malleable) Strong and resistant to breaking Have a characteristic sound when struck with an objet Have high melting and boiling points Have high densities Attracted to a magnet

Non Metals Exist as solids, liquids or gases at room temperature Do not reflect light well (no luster) Are brittle Cannot be hammered flat (nonmalleable) Can not be drawn into a wire (not ductile) Soft and bend or break easily (low tensile strength) Don’t have a characteristic sound when struck Are poor conductors of heat and electricity Have low densities Are not attracted to a magnet

Metalloids Are generally solid Can be shiny or dull May or may not be hammered flat May or may not be drawn into wire May or may not be brittle Conduct heat and electricity better than nonmetals, but not as well as metals Tend to make good semiconductors Have melting and boiling points that are widely varied Have densities that are widely varied

Electrons

Electron cloud Energy Levels Valence Electrons

Time to move… We are going to be electrons today! Lets go into the commons and practice

Electron Dot Diagram Symbol for the element surrounded by as many dots as there are electrons in its outer energy level. S

Lets Practice ~Complete the electron dot diagram and answer the questions N Element? # Electrons? # Valence Electrons?

Lets Practice ~Complete the electron dot diagram and answer the questions I Element? # Electrons? # Valence Electrons?

Elements, compounds and mixtures Page 37-38

Output part 1

Student Output-part 1 Create a Venn diagram

Example

Compounds

Why do element combine? Atoms are most stable when their electron shells are full.  Compound- a pure substance containing two or more elements that are chemically bonded

Ionic bond Ionic Bonds form when electrons are transferred from one atom to another, forming charged Ions which are attracted to each other. Elements tend to lose or gain electrons, forming Ions, to get a ' full other shell '. Ion-Atom that is positively or negatively charged because it has gained or lost electrons

Covalent Bond Covalent Bonds involve the sharing of electrons so that all atoms have ' full outer shells '.

Metalic Bond Bond formed when metal atoms share their pooled electrons

Output- Use the following words to complete the graphic organizer provided CovalentElectron cloudMolecule NucleusGain or loss of electrons

Ionic vs Covalent foldable…

Front Ionic Bond Covalent Bonds

Square # 1 Ionic Bond Atoms lose or gain electrons Between Metal and Nonmetal Covalent Bond Atoms share an electron Between nonmetal and nonmetal

Square # 2 Ionic BondCovalent Bond - 1 electron +1 electron Lithium + Flourine Sharing Electrons Oxygen+Oxygen

Square #3 Ionic BondCovalent Bond Li F + - O O

Square #4 Ionic Bonds LiF NaCL MgO Covalent bonds H2 H20 Co2

Chemical Bonds & Reactions

How Many Valence Electrons? Hydrogen Lead Xenon Sulfur Rubidium 1 Valence Electron 4 Valence Electrons 8 Valence Electrons 6 Valence Electrons 1 Valence Electron

The Octet Rule Atoms will combine to form compounds in order to reach eight electrons in their outer energy level.  Atoms with less than 4 electrons tend to lose electrons.  Atoms with more than 4 electrons tend to gain electrons. Be aware that there are some exceptions! CONSIDER EIGHT A HAPPY NUMBER FOR ATOMS!

Lewis Structure (Electron Dot Diagram) a way of drawing the outer energy level electrons (valence) of an atom The symbol for the element surrounded by as many dots as there are electrons in its outer energy level (valence) Examples How many valence electrons do each of these atoms have?

Making an Electron Dot Diagram Element “X” has 8 valence electrons Write down the element’s symbol and place the first two dots on any side of the symbol. Place the rest of the dots in either a clockwise or counter clockwise manner around the symbol, with no side receiving two dots until each side gets one. If this were an atom of an element from group 1, you would just place the one dot on any side of the element.

What Would the Electron Dot Diagram Look Like? H Sr O Ne How many valence electrons does each atom have? 1 Valence Electron6 Valence Electrons 8 Valence Electrons 2 Valence Electrons

Oxidation Number The charge that an atom would have if it lost or gained electrons; ionic charge Can be helpful in determining which atoms will interact or bond with each other Example: According to electron dot diagram for Magnesium, it has two valence electrons. Because Magnesium is “unhappy” with two, it will typically lose them. If this happens it will turn into a Magnesium ion. At this point it will have an oxidation number of +2. Mg 2+

What Could the Oxidation Number Be? H O Ne Sr +1 or -1 because it can gain or lose one electron -2 because it will gain two electrons 0 because it will not gain or lose electrons +2 because it will lose two electrons

3 Types of Chemical Bonds Ionic Covalent Metallic What can you describe about each of these bonds just by looking at the name?

Which different groups or families of elements will most-likely interact to create these types of bonds? IONIC BONDS - The force of attraction between oppositely charged ions. Occurs after a transfer or loss/gain of electrons Usually form between atoms of metals and atoms of non- metals Resulting compounds have a name that usually ends in –ide Example - Sodium Chloride (NaCl)Sodium Chloride (NaCl) Cl Na 1- 1+

COVALENT BOND A force that bonds two atoms together by a sharing of electrons Each pair of shared electrons creates a bond Usually occurs between atoms of non-metals Example – Water (H 2 O)Water (H 2 O) OHH

Results of Bonding Molecule A neutral group of two or more non-metal atoms held together by covalent bonds Type: Diatomic - molecules consisting of two atoms of the same element bonded together Examples: H 2, F 2, O 2, N 2 Compound A pure substance composed of two or more different elements (atoms) that are chemically combined Examples: CO, NO 2, NaCl What would you call something that has characteristics of both?

Molecule, Compound, or Both? H 2 Hydrogen NO 2 Nitrogen Dioxide Cl 2 Chlorine O 2 Oxygen NO Nitric Oxide CO 2 Carbon Dioxide N 2 Nitrogen H 2 O Water CH 4 Methane

Chemical Equation Shorthand form for writing what reactants are used and what products are formed in a chemical reaction Sometimes shows whether energy is produced or absorbed Examples: 2H 2 + O 2  2H 2 O CH 4 + 2O 2  CO 2 + 2H 2 O C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy

Components of a Chemical Equation 2H 2 + O 2 2H 2 O  (Reactants) (Products) (Yield) Chemical Formulas Chemical Formula Subscripts Coefficient Sometimes you will see a “yields” sign that looks like this. What do you think it means? Coefficient Subscript

Law of Conservation of Mass Proposed by Antoine Lavoisier In a chemical reaction, atoms are neither created nor destroyed All atoms present in the reactants are also present in the products Chemical equations must account for/show the conservation of mass  balancing equations H 2 + O 2 H 2 O  In its present form, does this chemical equation show a conservation of mass? How would you balance this equation to show the conservation of mass? 22 Reactants H  2 O  2 Products 4242 H  2 O 

Hints For Balancing Equations Count the atoms  List the number of atoms of each element to see which elements must be balanced Use a coefficient to add atoms to one side of the equation  Start with the reactant or product that has the greatest number of different elements Add a coefficient to another reactant or product  Make sure that the coefficients in your balanced equation are the smallest whole numbers possible (they should have no common factor other than one)