What law states that the physical and chemical properties of the elements are periodic within the sequence of their atomic numbers?

atomic law
periodic law
octet law
valence law

Periodic Law.

Explanation:

The Periodic Law states that the physical and chemical properties of the elements repeat in a systematic and predictable way when the elements are arranged in order of increasing atomic number.

Many of the properties are repeated at intervals.

When the elements are arranged correctly, the trends in element properties become apparent and can be used to make predictions about unknown or unfamiliar elements, simply based on their placement on the table.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.