Question

why is Oxygen kept under group 16?

Answer 1

because of the weight which is 16

Answer 2

oxygen group element, also called chalcogen, any of the six chemical elements making up Group 16 (VIa) of the periodic classification—namely, oxygen (O), sulfur (S), selenium (Se), tellurium (Te), polonium (Po), and livermorium (Lv). A relationship between the first three members of the group was recognized as early as 1829; tellurium was assigned its place by 1865, and polonium was discovered in 1898. In 2000, Russian and American physicists created livermorium, the sixth member of Group 16, in a particle accelerator.