What comes in contact with Sodium Hydroxide to form soap and glycerine it is a chemical change because you cannot reverse this change and also the products formed are the results of a chemical reaction.

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