I'm working on my science fair project. I placed 6 different metals (Al, Pb, Zn, Cu, Fe, and C) in muriatic acid.
Zn and Al reacted strongly and dissolved in about 3 minutes.
Pb, Cu, Fe, and C did not vigorously react.
I read that the number of electrons in the outer shell determine the reactivity of an element. Zn and Fe both have 2 electrons in the outer shell and the same number of layers. What made them react so differently in the acid?