Page 44 - Curriculum Visions Dynamic Book

Key facts about...
Chlorine
Chloride ions make up 0.015% of the Earth’s crust
About two and a half times as dense as air
The foundation for hydrochloric acid
Iodine
Poisonous in large amounts, but essential as a trace element to all plants and animals
A black solid at room temperature
Greenish yellow gas, chemical symbol Cl
Pungent smell
Found in common salt
Slightly soluble in water
Chloride ions make up nearly 2% of sea water
Atomic number 17, atomic weight about 35
Violet solid, chemical symbol I
Atomic number 53, atomic weight about 127
44
17th most abundant element in sea water; 62nd in the Earth’s crust
Mainly used as a disinfectant