What is atomic mass of an element stands for

Mass is a basic property of matter and is made of atoms. Atoms are made of electrons, protons, and neutrons. Protons and neutrons make up the majority of the mass in an atom. Atoms may vary in the number of neutrons they have (called isotopes), and therefore the exact atomic mass may vary from atom to atom

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.