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How does radioactive decay change one element into another?

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Bohr model diagram of a hydrogen atom showing a green nucleus labeled H, a single electron orbit, and text with atomic mass 1.008 and electron configuration 1. — atom The Bohr model describes the structure of atoms, in this case hydrogen.

Radioactive decay changes one element into another by altering the number of protons in an atom's nucleus, which defines its atomic number and chemical identity. This process, known as transmutation, occurs through specific types of decay:6123

Alpha decay: The nucleus ejects an alpha particle (two protons and two neutrons). This reduces the atomic number by two, transforming the atom into a different element.14
Beta decay: This process involves the transformation of a neutron into a proton (or vice versa) via the weak interaction. In negative beta decay, a neutron becomes a proton, increasing the atomic number by one. In positron emission or electron capture, a proton becomes a neutron, decreasing the atomic number by one.564

In contrast, gamma decay does not change the number of protons, so the element's identity remains the same. These transformations continue in a decay chain until a stable nucleus is achieved.14