Answer : The purpose of the zigzag line on the periodic table is to separates the metal from the non-metal.
Explanation :
Metalloids : These are the elements that shows both the property of metals and non-metals.
For example : Boron, silicon, germanium, arsenic, antimony, tellurium, polonium and astatine are the metalloids.
Metalloids separates the metals from the non-metals.
The zigzag line on the periodic table represent the metalloids.
Non-metals are found to the right side of the zigzag line that gains electrons to attain stability.
Metals are found to the left side of the zigzag line that loses electrons to attain stability.
Hence, the purpose of the zigzag line on the periodic table is to separates the metal from the non-metal.