More Lessons for High School Chemistry

Math Worksheets

A series of free High School Chemistry Video Lessons.

In this lesson, we will learn

- Nuclear Stability
- Transmutation
- Half-life
- Nuclear Fission
- Nuclear Fusion

Nuclear Stability

Nuclear stability is what makes certain isotopes radioactive. An isotope is unstable if it has a ratio of protons to neutrons that isn't within what is called the band of stability. Elements with atomic numbers greater than 70 are never stable. Unstable isotopes generally undergo transmutation, alpha decay or beta decay.

How the ratio of protons to neutrons affects a nucleus' stability.

Transmutation is the conversion of an atom of one element to an atom of another through nuclear reactions. Induced nuclear transmutation is transmutation which is induced by scientists by striking the nuclei with high volume particles. Transuranium elements are elements with atomic numbers larger than 92, or unnaturally occurring elements which must be created by bombarding uranium with protons.

How radioactive elements change their identities through transmutation.

Half-life

Half-life is the concept of time required for half of radioactive isotope's nuclei to decay. The amount remaining is calculated as the (initial amount) (1/2) (# of 1/2 lives)

Definition of half-life, and how to derive the expression for half-life for zero, 1st, and 2nd order reactions.

Fission

Fission involves splitting atomic nuclei into fragments. Atoms with mass numbers close to 60 have been found to be the most stable. Atoms with mass numbers lower than 60 undergo fusion while atoms with higher mass numbers undergo fission. The energy needed to break one mole of nuclei into individual nucleons is called binding energy.

In nuclear fission, an unstable atom splits into two or more smaller pieces that are more stable, and releases energy in the process. The fission process also releases extra neutrons, which can then split additional atoms, resulting in a chain reaction that releases a lot of energy. There are also ways to modulate and soak up the neutrons.

Fusion involves the combining of atomic nuclei. Atoms with mass numbers lower than 60 undergo fusion while atoms with higher mass numbers undergo fission. The energy needed to break one mole of nuclei into individual nucleons is called binding energy.

How radioactive substances undergo fusion to reach more stable states.

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