1. Isotopes and Nuclear Chemistry
Island of Stability

2. Isotopes
A variation of an element, that differs by the number of neutrons.
Protons CANNOT change – A proton is like an Atoms DNA, its what makes it an atom of a specific element
Electrons are so small – their mass is negligible to the mass of an atom
Neutrons are the only thing that can change – change the mass of the atom
When an atom varies in the number of neutrons, its mass also varies – these are called isotopes

3. Isotopic Notation How do we differentiate between different isotopes?
Isotopes can be written in a long format that uses the elements name and mass
Carbon – 12
Carbon – 13
Carbon - 14
Isotopes can be written with symbols just like elements can:

4. Practice with isotopic notation
Element
Isotopic Symbol
Mass Number
Atomic Number
Number of Protons
Number of Electrons
Number of Neutrons
Carbon – 14
Polonium – 210 27 13

5. Atomic Mass Recall what atomic mass is:
Average atomic mass is the mass of all the isotopes of an element combined
It is the mass given on the periodic table
It is calculated by taking the mass of each isotope of an element and multiplying each isotopes mass by its abundance then adding all the isotopes together.
(% of mass 1)(mass 1) + (% of mass 2)(mass 2) + (% of mass 3)(mass 3)…..
You would do this for each isotope of the element – some elements have many isotopes
Polonium has 25 isotopes and all are radioactive

6. Average Atomic Mass Problems:
Copper has two isotopes: 69.2% of all copper has a mass of 63 amu, while 30.8% of all copper has a mass of 65 AMU. What is copper’s average atomic mass?

7. Nuclear Chemistry
Radioactivity – the processes by which unstable nuclei achieve stability by releasing radiation
Radiation – the penetrating rays and particles emitted by a radioactive source
Radioactive Decay – the process in which unstable nuclei disintegrates
Radioisotopes – an isotope that has an unstable nucleus and undergoes radioactive decay

8. A reaction that results in a different nucleus
Nuclear Reactions
A reaction that results in a different nucleus
All reactions known up to this point, have not changed the nucleus
Law of Conservation of Mass
Nuclear reactions do not seem to follow this law.

9. Fission and Fusion Reactions
Nuclear decay that results from the nucleus of an atom splitting in to smaller pieces
Heavier atom becomes a lighter atom
The is nuclear energy on Earth
Requires little to no energy (usually)
Results in: free floating neutrons and photons (energy)
Nuclear reaction that results from two nuclei joining together to form one larger nucleus
Does NOT occur on Earth
If it did, it would solve our energy crisis
Releases gamma radiation for every reaction
This is what we could use for energy
Requires too much energy to start the reaction
Powers active stars

10. Fission and Fusion
Fission vs Fusion