Answer the atomic mass/amu one pls

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.

Phosphorous can form an ion called phosphide, which has the formula p3−. this ion can form an ion called phosphide, which has the formula p3−. this ion properties very similar to those of pforms when a phosphorus atom loses three protonsis called a cationcontains 18 electrons

How many atoms or molecules are there in a mole of a substance?