With an atom that has 5 protons and 3 electrons, the math is +5 added to -3. So what is the ion charge on the atom

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

gasoline is a mixture. it contains several different kinds of compounds that can be present in a variety of ratios.