Final answer:
Group 16 elements typically gain two electrons to complete their octet and form a 2- ion, such as oxide (O²-), to achieve a stable electron configuration mirroring the noble gases.
Step-by-step explanation:
The elements in Group 16, also known as the chalcogens, have six electrons in their valence shell. To achieve a stable electron configuration, these elements will typically gain two electrons to complete their octet, forming a 2- ion. For example, oxygen (O), which is in Group 16, will gain two electrons to achieve the electron configuration of neon (Ne), resulting in the oxide ion (O²-). Unlike metals that tend to lose electrons, the main-group nonmetals, including Group 16, tend to achieve an octet by accepting electrons. This is essential in chemical bond formation and for the stability of the atoms.