Here's why:
* Group Number and Valence Electrons: Group numbers on the periodic table generally correspond to the number of valence electrons (electrons in the outermost shell) an element has.
* Electron Configuration: Elements in Group 15 all have 5 valence electrons in their outermost shell. This is determined by their electron configuration, which for elements in Group 15 ends in ns²np³.
* Element 115: Element 115 (Moscovium) has the electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p³. It has 5 valence electrons (7s² 7p³), placing it in Group 15.
Therefore, a synthetic element with 115 protons would be a member of Group 15.
