Nuclear Reactions

fusion: A nuclear reaction in which nuclei combine to form more massive nuclei with the concomitant release of energy and often neutrons.

Nuclear reactions involve a change in an atom’s nucleus, usually producing a different element. Chemical reactions, on the other hand, involve only a rearrangement of electrons and do not involve changes in the nuclei. Different isotopes of an element normally behave similarly in chemical reactions.

• Fission.
• Fusion.
• Nuclear Decay.
• Transmutation.

The actual mass is always less than the sum of the individual masses of the constituent protons and neutrons because energy is removed when when the nucleus is formed. This energy has mass, which is removed from the total mass of the original particles.

Example: silver nitrate reacts with sodium chloride to produce silver chloride and sodium nitrate. A nuclear change — involves changes in nuclear structure, such as fission (splitting) of a nucleus or an atom, or fusion (combining) of neutrons and protons to form heavier atoms.

20.2: Nuclear Reactions

• Classes of Radioactive Nuclei.
• Nuclear Decay Reactions.
• Alpha Decay.
• Beta Decay.
• Positron Emission.
• Electron Capture.
• Gamma Emission.
• Spontaneous Fission.

To calculate the energy change for a nuclear reaction:

1. Calculate the sum of the masses of all of the products, and the sum of the masses of all the reactants,
2. Calculate the change in mass by subtracting the combined mass of the reactants from the combined mass of the products,

Ehrlich stated in 2018 that the optimum size of the global human population is between 1.5 and 2 billion. Geographer Chris Tucker estimates that 3 billion is a sustainable number.