Is a water molecule the smallest unit of water that has the properties of water

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

The characteristics of two different types of reactions are shown below: reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of an element. which statement is true about the atoms of the elements that participate in the two reactions? their identity changes in both reaction a and reaction b. their identity changes in reaction a but not in reaction b. their identity changes in reaction b but not in reaction a. their identity remains the same in both reaction a and reaction b.

How many valence electrons are in atom of radon?