If you look it up it will give you plenty of information. This is what I found:
The valence electrons of metals move freely in this way because metals have relatively low electronegativity, or attraction to electrons. The positive metal ions form a lattice-like structure held together by all the metallic bonds. ... When nonmetals bond together, the atoms share valence electrons and do not become ions
https://www.ck12.org/c/physical-science/metallic-bond/lesson/Metallic-Bonding-MS-PS/
This chemical reaction can also be written as
2C2H6+7O2-->4CO2+6H2O
This is a chemical reaction because reactants are converted into products. This is the combustion of ethane where ethane and oxygen have been converted into carbon dioxide and water
3 mass number- proton number
