no, both natural and synthetic rubber are polymers
rubber...
''Rubber'' is not an element, it's actually a compound it's formed with other element's needed.
NO
sodium..
Sulphur (Sulfur) is added to rubber in the process known as vulcanization.
There is not single element in bicycle tires. The rubber itself is vulcanized rubber, which contains carbon, hydrogen, and sulfur.
Magnesium
Sulfur
Oxygen, Carbon, and Hydrogen
Rubber is a natural organic compound. Chemical name for natural rubber is sis-polyisoprene.
sulfur
Sulphur