Final answer:
Selenium (Se) is similar to sulfur (S) in properties, as both are nonmetals in group 16, with similar chemical reactivities, forming similar negative ions, and being involved in biological systems and medicine.
Step-by-step explanation:
The element that has similar properties to sulfur (S), which is a nonmetal in group 16, is selenium (Se). Selenium, like sulfur, can form the selenide ion Se²⁻ and reacts similarly with metals and nonmetals. Both of these elements have six electrons in their outer shell, leading to similar chemical reactivities and formations of negative ions when they gain two electrons. Selenium can also replace sulfur in biological systems, which is an example of its chemical similarity.
For instance, selenium can be found in some amino acids that are analogs to those containing sulfur. Like sulfur, selenium can form various compounds, including binary selenides and organic selenium compounds, much like sulfur forms sulfides and organic sulfur compounds. The similar behavior of selenium and sulfur in biological systems and their uses in medicine highlights the importance of group 16 elements and their chemical behaviors.