Final answer:
Tin (Sn) has four valence electrons, as it is in group 14 of the periodic table, with its electron configuration ending in 5s2 4d10 5p2.
Step-by-step explanation:
Tin (Sn) has four valence electrons. It is located in group 14 of the periodic table, and elements in this group have four electrons in their outermost shell. The electron configuration for Tin is [Kr]5s24d105p2, and the electrons that reside in the 5s and 5p orbitals are considered valence electrons. These are the electrons most involved in chemical bonding and reactivity. Tin can form compounds with both divalent cations, such as Sn2+, and tetravalent cations, such as Sn4+, due to the inert pair effect. Tin's ability to donate or share these valence electrons is what allows it to participate in forming various types of chemical bonds.