What happens to the number of valence electrons as you move from left to right in the periodic table?

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

The element that has the greatest electronegativity is

How could a student test the effect of removing heat from a gas that is stored in a sealed container? what must occur in order for matter to change states?