How is the ionization energy, e, related to a period of elements?

Ionization energy increases as we move from left to right in a period.

Explanation:

Elements are arranged in 7 periods and 18 groups in a periodic table.

Ionization energy is defined as the energy required to remove an outermost electron from from an isolated gaseous atom.

As, we move from left to right in a period, the electrons get added up into the same shell and is more attracted towards the nucleus.

This added electron requires more energy to be removed because it is attracted more towards the nucleus.

Hence, in a period, ionization energy increases.

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.

give me abc and i will get it for u.