1. Atoms,Elements, and Compounds

2. ATOMS
Atoms are the basic building blocks of matter that make up everyday objects.
A desk, the air, even you are made up of atoms!
Matter- Anything that takes up space

3. Parts of the Atom
Electron = negative particle circling the nucleus (each electron has a –1 charge)
Proton = positive particle found in the nucleus (each proton has a +1 charge
Neutron = neutral particle found in the nucleus (a neutron has no charge)

4. Atomic Number
The number of protons in an atom defines what element it is. 
For example carbon atoms have six protons, hydrogen atoms have one, and oxygen atoms have eight. 
The number of protons in an atom also determines the chemical behavior of the element.

5. Carbon and the periodic table
Atomic symbol= C
Atomic number 6
Mass number= 12
Atomic #=# protons
#protons=#electrons
Mass number= weight of protons + neutrons (rounded)
Electrons add little weight and are insignificant on a periodical table
Protons and Neutrons weigh the same: 1 a.m.u.

6. ELEMENTS
substances that cannot be decomposed or broken into simpler substances by ordinary chemical means.
Elements are made up of only one kind of atom [ex. Carbon(C), oxygen(O2), helium(He)]

7. Element Name and Symbol
Atomic Symbol: The atomic symbol is one or two letters chosen to represent an element ("H" for "hydrogen," etc.). 
Memorize the symbols/ names of the following:
C Carbon
O Oxygen
H Hydrogen
He Helium
Na Sodium
Fe Iron
N Nitrogen
S Sulfur

8. Compounds Substance formed by a combination of two or more elements
(ex. Water (H2O) has hydrogen and oxygen

9. Mixtures/Solutions
Mixture- Substances that do not dissolve together but mix
Solutions – Mixture that is evenly distributed throughout the solution
Solution

10. Mixtures Solution Solute- NaCl Solvent- water
NaCl Dissolving in Water When an ionic compound such as sodium chloride is placed in water, water molecules surround and separate the positive and negative ions.

11. Mixtures
Mixture
Different particles not dissolved

12. Atom vs. Molecule
Atom – the smallest possible particle of a molecule that retains its chemical properties
Molecule - two or more atoms in a definite arrangement held together by chemical bonds
Example: A Hydrogen Atom
Water is always H2O

13. What is in a Molecule Formula’s H2O H2O Water Ammonia NH3
Subscript (Little number after an element symbol in a molecule) means there are that number of the previous Atom
H2O Water
2 Hydrogen 1 Oxygen
Ammonia NH3
1 Nitrogen 3 Hydrogen
Sucrose C12H22O11
Table Salt NaCl
Sodium Bicarbonate NaHCO3
H2O

14. Definitions
Bond - joins two atoms together The Octet Rule- Says that atoms tend to gain, lose or share electrons so as to have eight electrons in their outer electron shell.
-To be stable atoms must have their outer orbit filled.
-Usually the outer orbit holds 8 electrons
-Hydrogen and Helium have an outer orbit that only holds 2 electrons.
Chemical bond – a force that holds two atoms together (occurs because atoms want to achieve stability ) atoms want to have a complete outermost energy level

15. Types of bonds
Ionic bonding – bonding that involves a transfer of electrons (one atom gains electrons and one atom loses electrons) ions are formed
Electrons have a -1 charge
A positive ion is formed when a electron is given off
A negative ion is formed when a electron is gained

16. Types of Bonds
Covalent bonding - occurs when atoms share electrons to fill outer orbits. Water is 2 Hydrogen and 1 Oxygen covalently bonded.

17. Covalent bonding - side + side
Electrons in a covalently bonded compound are not shared equally
Larger atoms tend to hog more electrons.
In water Oxygen hogs
more of the electrons and
therefore the oxygen side
is more negative and the
hydrogen side is slightly
positive
-When there are different
charged sides the molecule
is said to be polar.
- side
+ side

18. Hydrogen Bonds
Attraction that forms between two polar molecules (when hydrogen is present).
The positive side of one polar molecule attracts and is “bonded” to the negative side of another polar molecule.

19. Compound
A substance formed by the combination of two or more elements in definite proportions.
Exp: NaCl, Salt