1. Ions
Ions: are charged atoms because number of protons don’t equal number of electrons.
Ions: are negatively charged when they gain electrons, they are called anions.
Ions: are positively charged when they lose electrons, they are called cations

2. Isotopes Isotopes: Are two or more forms of an element.
Isotopes: have the same number of protons
Isotopes: have a different number of neutrons & therefore a different mass.
Ex. 35Cl & 37Cl
12C & 14C
Isotopes: have the same physical & chemical properties,
Isotopes: have different nuclear properties. Some isotopes are unstable or radioactive (radioisotopes), which means that the nucleus has a tendency to break apart and eject very high energy particles into its surroundings.

3. Isotopes Isotopes:. Can be unstable or radioactive
Radioisotopes: the nucleus breaks apart ejecting very high energy particles.
Some uses of radioisotopes are:
diagnose medical problems (thyroid disease, iodine-131)
radiation therapy cobalt-60
carbon-14 dating of ancient humans and artifacts
smoke detectors contain americium-241
CANDU reactors uranium-235
heavy water deuterium
plutonium-241 spent fuel in a light-water power reactor

4. Lewis Dot Diagrams "electron dot" diagrams
elements in a family on the periodic table have the same number of electrons in the outer shell.
valence electrons  the electrons that are involved in chemical bonding.
To draw a Lewis dot diagram,
write the symbol (this represents the nucleus & inner electrons)
draw the valence electrons as dots around the symbol.
Put the first four dots on each side, then fill in the sides to a maximum of two dots per side.
Ex: H Ca O Ne

5. Chemical Bonding
During chemical reactions, electrons are rearranged between atoms resulting in bonds being formed or broken.
Generally, electrons are arranged so that their outer energy level is full.
(same number of electrons as the closest noble gas).
Two types of bonds are generally formed.
Ionic bonds  transfer of electrons from a metal to a non-metal.
Covalent bonds  sharing of electrons between two or more non-metals.

6. Lewis Diagrams of Chemical Bonds
Ionic Bonds:
Example: bond between lithium & oxygen
Li O Li →
Naming ionic compounds:
The metal keeps it’s name
The non metal takes the ending ide
Example: NaCl sodium chloride
MgF2 magnesium fluoride

7. Lewis Diagrams of Chemical Bonds
Covalent Bonds:
Example: bond between oxygen & oxygen
O O → (this is a diatomic gas)
O=O oxygen gas makes a double covalent bond

8. Complete the following:
compound
Number of types of elements
Total number of elements
Type of Bond
Lewis Diagram
NaCl
Mg F2 O2
CuSO4

9. Atoms & Their Electrons
34min
(How O, N & C bond 20 min)
The science of snowflakes
(4.5 min)