1. What are Isotopes? understand what an isotope is
understand conventions for representing isotopes.

2. Activity: What did you find out?
Construct a carbon atom which has six protons, six neutrons, and six electrons, and one which has six protons, eight neutrons and six electrons.
Count the protons in their carbon atom and determine the atomic number.
Discuss the structure of an atom.
What are the parts of an atom?
What part defines the element?
What parts can change in number and remain the same element?
What is different about these two atoms?
What did you find out?
All isotopes of carbon will have the atomic number for carbon.

3. ISOTOPES: (equal place of atomic #)
Isotopes: are different atoms of a element that have same # of protons BUT different # of neutrons.
Isotopes have different mass numbers but same atomic # ie. Chlorine-35 and chlorine-37 (atomic # 17)
FORMULAES YOU NEED TO KNOW:
1) Mass # = atomic # (number of protons) + # neutrons
2) # Neutrons = mass # - atomic #

4. What are isotopes? An atom has protons and neutrons in its nucleus.
The number of protons determines the atomic number.
Neutrons provide space between the protons to help bind the nucleus.
It is possible to have different numbers of neutrons in atoms that have the same atomic number.
These atoms are called isotopes of each other.
Note: all isotopes of the same element have the same atomic number. This is because the number of protons determines atomic number.

5. Representing Isotopes:
• Establishing that mass number differs between
isotopes of the same element however atomic number
remains the same
Representing Isotopes:
Isotopes use atomic notation (nuclear symbol)
Chemical symbol + atomic number + mass number.
chemical symbol
mass number
Atomic number
Word equation of writing isotopes:
Potassium-39, potassium-40, potassium-41

6. Focus Questions: What is an isotope?
What parts of the atom are displayed in the examples?
What determined the name of the atom in the examples?
What determined the number included in the name?
What is the convention used to write the name of an isotope?
Why is it important to include this information when writing the name of an isotope?