Look at the protons and electrons and rememeber metals want to get rid of electrons to be perfect. Nonmetals are wanting to take in. Metals are negatives in electrons. Opposite for nonmetals.
Metal period- Reactivity Gets smaller as you move from left to right.
Group- Reactivity gets bigger as you move down a group.
The only one I know for sure is Mass is always conserved In a Chemical reaction.
Answer: I believe that it's electrons please let me know if it was right or what it was!
Hope this helps!!! Good luck!!! ;)
