The full electron configuration for the Sn²⁺ ion (tin ion with a +2 charge) can be determined by first identifying the electron configuration of a neutral tin atom.
The neutral tin (Sn) atom has an atomic number of 50, which means it has 50 electrons. The electron configuration for a neutral tin atom is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p²
When tin loses two electrons to form the Sn²⁺ ion, it loses the two outermost electrons, which are in the 4p subshell. Thus, the electron configuration for the Sn²⁺ ion becomes:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰
This indicates that the Sn²⁺ ion has a total of 48 electrons, which corresponds to the configuration listed above.