1. WE ARE CHILDREN OF THE UNIVERSE
STARDUST IS THE “STUFF” OF LIFE

2. We are the children of the Universe…… Made of the same star dust that is created and recycled in an ongoing cycle initiated with the Big Bang…..

3. Early Chemistry Early Chemists only believed in 1 element: Dirt
Later Chemists believed in 4 elements:
Air
Earth
Fire
Water

4. Periodic Table of Elements
Elements are
Arranged according
To their unique size
Weight and properties

5. Periodic Table Notation:
Chemical elements are represented on the periodic table using the following format.
The letter is an abbreviation of Element Name
Atomic Number is the number of protons the atom has.
Mass number is the total mass of the element (protons + neutrons.

6. Basic Chemistry All Matter in universe is composed of Atoms
Elements are composed of only 1 type of atom.
ELEMENTS are pure substances that cannot be broken down or changed under ordinary means

7. Atoms Are the .……
Smallest piece of an element that still has all the same characteristics of that element (an atom gold, for example, is still gold)

8. An Atom (up close) Atoms Consist of: NUCLEUS protons neutrons
Orbital Cloud
electrons

9. Summary of Subatomic Particles:
Particle Name
Location
Charge
Mass
Electron
Orbitals -1 ~0
Proton
Nucleus +1 1
Neutron
No Charge

10. Definitions to Know:
Atomic Number = # of protons
Atomic Mass = # of protons PLUS # of neutrons
One can calculate the number of neutrons an atom has by subtracting the atomic number (# protons) from the mass number.

11. Isotopes:
Atoms having the same atomic numbers and different mass numbers are called Isotopes
Isotopes are atoms of the same element with different numbers of neutrons (mass).
They react chemically the same as the “normal” form of the element
They are frequently radioactive
Hydrogen Isotopes

12. Let’s look at the isotopes of carbon
There are only more neutrons in the nucleus, but the same Number of protons
Atomic Mass: weighted average of the element’s isotopes

13. Atoms are Electrically Neutral
The number of protons (+) are equal to the number of electrons (-)
Therefore, atoms have no overall charge
Atoms can GAIN, LOSE or SHARE ELECTRONS
Electrons are involved in forming chemical bonds
Atoms having a CHARGE are called IONS (we’ll discuss this later)

14. Interactions of Matter:
Atoms interact through the process of chemical bonding.
Process is determined by the number of electrons found in the outermost energy level of an atom
Valence Electrons
Involves the transfer & sharing of electrons between atoms. (covalent & ionic bonding)

15. ELECTRON / ENERGY LEVEL RULES:
Atoms seek to have a “full” outermost energy level. All chemical reactions happen to accomplish this.

16. Why do Compounds Form?
Atoms are only happy when their outermost energy level is “filled” with electrons (valence electrons)
By gaining, losing or sharing valence electrons, atoms can (fill their valence shell) and find happiness
The forces of attraction holding atoms together (as a result of the above) are known as CHEMICAL BONDS
ATOMS SEEK STABILITY 

17. Involved in chemical Bonding
Valence Electrons:
Involved in chemical Bonding
Figure 2.7

18. Types of Chemical Bonds
Bonds holding atoms together:
Ionic bonds
Covalent Bonds
Metallic Bonds
Bonds Holding Molecules together:
Hydrogen Bonds
Van der Waal Forces

19. Ionic Bonds
When an atom loses or gains electrons, it becomes electrically charged.
Charged atoms are called ions.
Ionic bonds are formed between oppositely charged ions.
Ionic Bonds

20. Sodium gives away electron Chlorine
IONIC
BOND
Positive Ion
Negative Ion
Opposites Attract: It’s Chemistry 

21. Ionic bonds are the strongest type of bond 
Ionic bonds always involve:
The exchange of electrons
The atom that donates
The electron (s) becomes
A positive ion
The atom that gets the
Electron (s) becomes a
Negative ion

22. Ionic Bonds:
Ionic bonds form when 1 atom “gives” one or more electrons to another atom to complete their outer energy levels.
This results in 1 positively charged ion & 1 negatively charged ion
Since opposite charges attract, they come together and bond.

23. Covalent bonds involve the sharing of electrons
Covalent verses ionic bond
Electrons
Move between
Two or more
Atoms
This makes
Both atoms
Happy 
Covalent bonds
Not as strong as ionic

24. Covalent Bonds:
Atoms can share more than 1 pair of electrons between them forming double and triple bonds
A Molecule is a group of 2 or more atoms held together by covalent bonds.

25. How many pairs of electrons can atoms share ?
Covalent bonds involve the sharing of electrons (no actual exchange of electrons, so no ions are formed)
However, atoms can share one , two or three pairs of electrons.
Single bonds result from sharing one pair of electrons
Double bonds involve the sharing of two pairs of electrons
Triple bonds (you guessed it) share three pairs of electrons

26. Covalent bonds Bonds can be ILLUSTRATED AS
A straight line (s) or As electron “DOTS”
The more bonds (shared electrons) between two atoms, the stronger are the forces of attraction

27. More on Covalent Bonding
Covalent bonds can be represented as:
Straight lines each line represents a shared pair of electrons.
Models
2-D or 3-D molecular models

28. Example Formulas: Chemical Name Chemical Formula Structural Formula
Water
H2O
Carbon Dioxide
CO2
Methane
CH4
Glucose
C6H12O6

29. Structural and Chemical Formulas:
Chemical formulas show the number of and types of atoms in a molecule
Structural Formulas are used to graphically represent a chemical formula
Useful in visualizing how chemicals react and form new ones.
H20

30. Covalent Bonds:
Covalent bonds form when 2 atoms “share” one or more electrons between them.
There are 2 types of covalent bonds:
Non-Polar Covalent bonds form when two atoms share electrons equally
Polar Covalent bonds form when two atoms share electrons unequally.

31. Covalent Bonds ; NOT always is the sharing of electrons EQUAL 
When electrons are not shared equally between atoms the molecule is described as being “POLAR”; This happens…
When electrons are pulled closer to one atom in a molecule, a slightly negative charge develops around that atom
The other atom in the molecule develops a slightly positive charge (since the electrons are pulled away)

32. Polar molecules are created by the unequal sharing of electrons
The water molecule is
a good example of a
Polar covalent molecule.
Notice the “slightly”
Positive charge around the Hydrogen, and Negative charge around the more electronegative Oxygen

33. Hydrogen Bonds are forces of attraction between MOLECULES
Hydrogen bonds Exist
between molecules
And not between
The atoms of a
molecule.

34. A HYDROGEN BOND always involves a Hydrogen atom
A Hydrogen bond is an INTERMOLECULAR BOND that always involves a Hydrogen (H) atom of one molecule and an atom of another (nearby) polar molecule that has a slightly negative charge.
Oxygen (O), and Nitrogen (N) are atoms often bonded to Hydrogen in a Hydrogen bond

35. Chemical Reactions: Reactants = Substances entering the reaction
A Chemical Reactions occur whenever chemical bonds are formed or broken.
Reactants = Substances entering the reaction
Products = Substances existing the reaction
Catalysts = Substances which speed up the rate of a reaction (enzymes are organic catalysts)

36. Brain Break 