What is the difference between a family of elements and elements in the same period

Why are people not able to scuba dive in the deep part of the ocean

The name of the ion, s2-, is: sulfurous ion sulfide ion sulfur ion sulfate ion

This flow chart shows the amount of energy that is emitted by each type of light. ultraviolet > blue light > yellow light > red light (maximum energy) (minimum energy) in an experiment, shining which type of light on a strip of metal would be least likely to produce the photoelectric effect? ultraviolet light dim blue light bright red light bright yellow light