Why is paper towel absorbing water a chemical change

it is not a chemical change

Explanation:

it is a physical change as a paper towel can be  dried in the sun to turn into a regular paper towel thus proving that a paper towel absorbing water is a physical change not a chemical change

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.