What is added to the name of a base unit to indicate a fraction or a multiple of the base unit?

Ionic compounds are made of ions, and yet the overall charge of an ionic compound is neutral. why?

Achange in the number of neutrons in an atom will change an blank . when the number of protons changes in an atom, a new element will form.

1) describe the physical layout of the ocean floor ? 2) explain how the dumbo octopus swims differently than other octopus species and why this would be an advantage in the aphonic zone . 3) why are the types of organisms that live at each underwater hot vent so dramatically different ?