How does beta-minus decay change uranium-239 into neptunium-239?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — transuranium element Modern version of the periodic table of the elements (printable).

In the process of beta-minus decay, a neutron within the nucleus of a uranium-239 atom is transformed into a proton. This transformation occurs via the weak force, which results in the emission of a high-velocity electron (a beta particle) and an antineutrino.123

Because the beta particle carries away a single negative charge, the nucleus gains one additional positive charge, increasing its atomic number from 92 to 93. Since the beta particle has negligible mass, the total mass number of the nucleus remains 239. The resulting nucleus, now possessing 93 protons and a mass number of 239, is an isotope of the element neptunium.1