Final answer:
A Group VA (15) element achieves a noble gas configuration by gaining three electrons, as this fulfills its valence shell and stabilizes the atom, similar to the noble gases' electron configuration.
Step-by-step explanation:
The electronic changes that will cause a Group VA (15) element to achieve a noble gas configuration is gaining three electrons. Group VA elements have five electrons in their outermost shell and require three additional electrons to fill their valence shell to achieve the most stable electron configuration, similar to the noble gases. For example, phosphorus (P) has an electronic configuration of 1s²2s²2p¶3s²3p³. If phosphorus gains three electrons, it will become a phosphorus trianion, P³-, and its new configuration will be 1s²2s²2p¶3s²3p¶, which matches the noble gas configuration of argon (Ar).
On the contrary, other groups in the periodic table have different requirements for achieving stability: Group I elements need to lose one electron, and Group XVII elements need to gain one electron to achieve a noble gas configuration. These behaviors in electron gain or loss are due to each group's unique electronic structure and the consequent stability of the resulting ions.