Silver (Ag) is known to typically form a 1+ ion, while the elements immediately adjacent to it in the periodic table, such as copper (Cu) and gold (Au), tend to form 2+ ions. This behavior can be explained through an understanding of electron configurations and the stability of electron shells.
Silver has the electron configuration of [Kr] 4d10 5s1. When it forms a 1+ ion, it loses the single electron in the 5s orbital, resulting in a stable configuration of [Kr] 4d10. This full d-subshell is relatively stable, which explains why silver prefers to lose just one electron.
In contrast, the elements to the left and right of silver, such as copper with the configuration [Ar] 3d10 4s1 and gold with [Xe] 4f14 5d10 6s1, tend to lose two electrons (from both the s and sometimes the d orbitals) to achieve a more stable configuration, especially in the case of copper. The formation of a 2+ ion allows these elements to also attain a filled or half-filled d-subshell, which is energetically favorable due to electron repulsion and stability considerations.
Overall, the tendency of silver to form a 1+ ion rather than a 2+ ion can be attributed to its stable electron configuration after losing a single electron, and the general trends in ion formation among its neighboring elements.