It is a physical change because only the states as being changes, not the actual bonds in the compound.
Fireflies. LED, fluorescent light
Atoms are made up of three basic particles: protons, electrons, and neutrons. Protons and neutrons are found in the nucleus, and the nucleus is found in the very center of an atom. Protons are positively charged whereas neutrons have no charge.
Electrons are found on the electron shells, and the electron shells are found in in the outermost region of an atom. The outermost electron shell contains valence electrons. Electrons are negatively charged.
The number of protons vary depending on the atomic number of an atom. The number of neutrons vary depending on the atomic mass and atomic number of an atom. To find the neutron you must subtract the atomic mass from the atomic number. The number of electrons in a neutral atom also vary depending on the atomic number.
Sorry this is so long. I didn't quite understand your question so I added the last paragraph in just in case it was helpful in any way. I hope I helped!
