True or false? an elements reactivity id determined by the number of protons found in an atom of the element?me

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?

Classify this reaction: 2al+n2-> aln.

State one important difference between a physical change and a chemical change?