Which reaction converts an atom of one element to an atom of another eleme

This reaction is called nuclear transmutation. Atoms of one element can be changed into atoms of another element by a process which takes place through nuclear reactions whereby an outside particle reacts with a nucleus, or through what is known as radioactive decay,  a process where no outside particle is required.

Not all radioactive decay or nuclear reactions result in transmutation but all transmutation is caused by either nuclear reaction or radioactive decay. For example when Uranium -235 undergoes beta decay, it forms thorium-231

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.

answer; capital earns interest; entrepreneurship receives a profit or incurs a loss;