Chlorine
Fluorine
Oxygen
Iodine
The substance coated on plastic tape recorder tapes is
The substance most commonly used as a food preservative is
The substance that cannot be used as an insecticide is
The substance that is added to make natural rubber strong & more bouncy is
The substance that is least prone to catch and spread fire is
The temperature of oxy-acetylene flame is around
The term meaning copper demon denotes the metallic element
The third shell of an atom can have a maximum of _ electrons.
The three elements most needed in common fertilisers are:
The two metal ions that cause hardness to water are:
