Upon completion of this topic, learners will be able to:

• explain how nuclear reactions differ from chemical reactions.

Nuclear reactions are not considered to be ordinary chemical reactions. The governing principles for ordinary chemical reactions deal with the rearrangement of electrons; this rearrangement occurs as the result of electron transfer or electron sharing. In nuclear reactions, it is nuclei rather than electron arrangements that undergo change.

Specific atoms, in nuclear chemistry discussions, are called nuclides rather than isotopes. The term nuclide refers to atoms of either the same or different elements.

A nuclide is an atom with a specific atomic number and a specific mass number. In practice, the designation nuclides is used to describe atoms of different elements and the designation isotopes is used to describe different types of atoms of the same element. The species ¹²₆C and ¹⁶₈C are nuclides of different elements, while the species ¹²₆C and ¹³₆C are isotopes of the same element.

Another type of radioactivity, known as nuclear transmutation, results from the bombardment of nuclei by neutrons, protons, or other nuclei. An example of a nuclear transmutation is the conversion of atmospheric ¹⁴₇N to ¹⁴₆C and ¹₁H, which results when the nitrogen isotope captures a neutron (from the sun).