Deuterium is an isotope of hydrogen. the nucleus of a deuterium atom consists of one proton and one neutron. when two deuterium nuclei fuse, helium-3 is formed, and a neutron is emitted. give the equation that illustrates this process?

Explanation:

Remember that the atomic number of an element is the number of protons and the mass number is the number of protons plus neutrons.

1) Deuterium representation:

2) Helium-3 representation:

3) Neutron representation

4) Nuclear equation:

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.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).