1. Bell Ringer: What is it’s Element Symbol? What is it’s Atomic #?
Please pull out your Periodic Table
Lets looks at the element: Chlorine
What is it’s Element Symbol?
What is it’s Atomic #?
How many Protons?
How many Neutrons?
How many Electrons?
Draw a Bohr model of Chlorine
How many electrons are in the valence shell?
Is the element stable or unstable?

2. Chlorine What is it’s Element Symbol? Cl What is it’s Atomic #? 17
How many Protons? 17
How many Neutrons? 18
How many Electrons? 17
Draw a Bohr model of Chlorine
How many electrons are in the valence shell? 7
Is the element stable or unstable? Stable Cl
P:17
N:18

3. What is theSpringfield High School Mascot on the Simpsons?

4. Isotopes
Isotopes: Atoms of the same element that differ in the number of neutrons that they contain.
Radioactive Isotopes: Isotopes are unstable and break down at a constant rate over time. Dangerous but has practical uses.
Dating rock layers, cancer treatment, food preservation.

5. Isotopes of Carbon Nonradioactive carbon-12 Nonradioactive carbon-13
6 electrons
6 protons
6 neutrons
6 electrons
6 protons
7 neutrons
6 electrons
6 protons
8 neutrons

6. Chemical Compounds Compound: A combination of two or more elements.
Molecule: the smallest unit of a compound.
Written as a chemical formula.
Water is written as H2O because it contains two atoms of Hydrogen and one atom of Oxygen.
Table Salt is written as NaCl because it has one atom of Sodium and one atom of Chlorine.

7. Let’s take a look at Chemical Formulas
H2O
Subscript: Tells you how many of each atom are in the molecule. If there is no subscript, there is one of that atom.
2H2O
Coefficient: Tells you how many of each molecule you have. If there is no number in front then there is one of that molecule

8. Count the Atoms! H H2 = H:1 H2O 2H2O
***Molecules in parentheses are called Polyatomic Ions and always occur together when they bond.
H2(SO4)
C7H5(NO2)3
= H:1
= H:2
= H:2 O:1
= H:4 O:2
= H:2 S:1 O:4
= C:7 H:5 N:3 O:6

9. Ionic Bond = Giver + Taker Givers won’t bond with Givers
Chemical Bonds
Ionic Bonds: Occurs when one or more electrons are transferred from one atom to another.
Ion: an atom with a positive or negative charge.
Ionic Bond = Giver + Taker
Givers won’t bond with Givers

10. Ionic Bonds Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
Protons +17
Electrons -17
Charge
Protons +11
Electrons -10
Charge
Protons +17
Electrons -18
Charge

11. Covalent Bond = Taker + Taker
Chemical Bonds
Covalent Bond: Occurs when two atoms share electrons
Covalent Bond = Taker + Taker
Givers won’t bond with Givers

12. Complete the following today
Counting atoms worksheet
Chemical bonding worksheet
Anything you didn’t finish last class