Answer:
Natural chemicals:
1) Water: H₂O
2) Oxygen: O₂
3) Nitrogen: N₂
Artificial chemicals:
1) PVC, polyvinil chloride (a plastic used in toys and hoses, among others)
2) PE, polyethilene (a plastic used in containers, among others)
3) Baquelite (a plastic used in pan handles, among others)
Explanation:
1) All the substances are chemicals, since chemist is the science of the elements and compounds, their properties, compositions and transformations.
2) Natural chemicals are those that you find in nature: the plants, the air, the water sources, the soils, all have chemicals, which are considered natural.
The oceans have sodium chloride, iodine, and other salts.
The air has nitrogen, oxygen, carbon dioxide, argon, methane.
The solid part of the Earth has salts, elements and minerals: gold, carbon, aluminum, silicon, phosphorus, among many others.
The plants elaborate sugar (glucose), oxygen and water.
So, the nature is the biggest chemical laboratory. And all those are natural chemicals.
2) Artifical chemicals are those created by the man.
The man creates chemicals to imitate the nature, tho enhance it, for scientific reasons, or just for fun.
Some of the chemicals made by the man are equal to those in nature (or almost equal). Some are simply purification of chemicals made by the nature. Others are great creations, even some are results of the luck, others are authentical result of well aimed work.
Artificial flavors, artificial fabrics, a huge divertity of plastics, food, medicines, detergents, soap, among other petrochemicals, are some artificial chemicals.
Both natural and artificial chemicals may be benefitcal or harmful. It is the use, the doses, and the intentions what may do the difference between good and bad chemicals; not the origin.