The Structure of the AtomOn 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 atomsPage 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 TablePage 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

C6

Carbon12.011

Atomic Number- Number of protons in the nucleus

Element Name

Symbol

Atomic MassAverage 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

NElement?

# Electrons?

# Valence Electrons?

Lets Practice ~Complete the electron dot diagram and answer the questions

IElement?

# Electrons?

# Valence Electrons?

Elements, compounds and mixturesPage 37-38

Output part 1

Student Output-part 1Create 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

• Covalent Electron cloud Molecule

Nucleus Gain or loss of electrons

Ionic vs Covalent foldable…

FrontIonic Bond

Covalent Bonds

Square # 1Ionic Bond• Atoms lose or gain electrons

• Between Metal and Nonmetal

Covalent Bond• Atoms share an electron

• Between nonmetal and nonmetal

Square # 2

Ionic Bond Covalent Bond

-1 electron+1 electron

Lithium + Flourine

Sharing Electrons

Oxygen+Oxygen

Square #3

Ionic Bond Covalent Bond

Li F

Li F+ -

O O

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?

Mg:Magnesium

Al :.

Aluminum

N :.. .

Nitrogen

Making an Electron Dot DiagramElement “X” has 8 valence

electrons

X. X : X :.

X :..

X :.. . X :

. .. . X :

. .: . X :

. .:. .

1 2 3

4 5 6 7

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 elementfrom group 1, you would just place theone 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 Electron 6 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:

Mg:MagnesiumAccording 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. Mg2+

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 notgain 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 thesebonds just by looking at the name?

Which different groups or families

of elements will most-likely

interact to create these

typesof 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)

Cl Na1- 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 (H2O)

-

-

-

-

--

-

--

-

OH H

Results of BondingMolecule

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:

H2, F2, O2, N2

Compound

A pure substance composed of two or more different elements (atoms) that are chemically combined

Examples:

CO, NO2, NaCl

What would you call something that has characteristics of both?

Molecule, Compound, or Both?

H2

Hydrogen

NO2

Nitrogen Dioxide

Cl2

Chlorine

O2

Oxygen

NO

Nitric Oxide

CO2

Carbon Dioxide

N2

Nitrogen

H2O

Water

CH4

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:

2H2 + O2 2H2O

CH4 + 2O2   CO2  +  2H2O

C6H12O6 + 6O2 6CO2 + 6H2O + energy

Components of a Chemical Equation

2H2 + O2 2H2O

(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

H2 + O2 H2O

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?

2 2Reactants

H 2O 2

Products

42

H 2O 1

42

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)