1. Isotopes
Objectives:
5.2 To identify the advantages & disadvantages of using isotopes in industry, medical science, basic research & in the environment

2. Isotopes:
Are atoms of the same element, but have a different number of neutrons
ex. Carbon can have 6 or 8 neutrons C 12 6 C 14 6 OR
6 neutrons
8 neutrons

3. Isotopes: C C 12 6 14 6 Have the same number of protons & electrons
Have the same atomic number
Have the same chemical reactivity C 12 6 C 14 6

4. Ex #1 different What statement is false?
A) Isotopes have the same number of protons
B) Isotopes have the same number of neutrons
C) Isotopes have the same number of electrons
different

5. Different # neutrons
Same # protons
Ex #2
Given the three hypothetical atoms below, which are isotopes of the same element? A 10 6 B 10 5 C 12 6
isotopes
4 neutrons
5 neutrons
6 neutrons
6 protons
5 protons
6 protons

6. Ex #3 First Next 2 isotopes
Different # neutrons
Different Atomic Mass
Same Atomic Number
Ex #3
According to the graph below, how many isotopes of nitrogen (N) are there? 15 14
First
Next
Find atomic number of N
Trace up – each point represents an isotope
Atomic Mass
2 isotopes 13 12 5 6 7 8
Atomic Number

7. Ex #4 Finally First Next Next 3 isotopes
According to the graph below, what is the mass number of each isotope of oxygen?
3 isotopes 10
Mass number = 18
Finally 9
Mass number = 17
First
Next
Next
Find the number of protons
Trace up – each point represents an isotope
Add the number of protons & neutrons together for each isotope
Number of Neutrons
Trace along & find the number of neutrons for each isotope 8
Mass number = 16 7 7 8 9 10
Number of Protons

8. Isotopes: Occur naturally & are made artificially
Most natural isotopes are stable
Some natural & artificial isotopes are unstable (the nucleus “breaks apart”)
When unstable, release radiation (radioisotopes)

9. Radioisotopes: Unstable isotopes (radioisotopes) can be used for:
Cancer therapy
Medical diagnosis
Nuclear power plants
Irradiation of foods
Nuclear weapons

10. Key Points to Remember
Isotopes are atoms of the same element, but with a different number of neutrons
Same atomic number, number of protons & electrons and chemical reactivity
Natural isotopes tend to be stable
Artificial isotopes are not stable & can release radiation