Compare the polymerisation reaction used to produce poly(ethene) with the polymerisation reaction used to produce a polyester.

See explanation

Explanation:

Polymerization is the process whereby two or more monomers link together to form a compound of high molecular mass called a polymer.

There are two kinds of polymers;

-Addition polymers

-Condensation polymers

Addition polymers are formed by the joining of two or more monomers  to form a polymer without the elimination of a small molecule.

Condensation polymers are formed by the joining of two or more molecules  to form polymers with the elimination of a small molecule.

The main difference between polyethene and polyester is that polyethene is an addition polymer while polyester is a condensation polymer.

In polyethene, ethene molecules are joined together having the repeating unit as [-CH2-CH2-]n.

In polyester, the polymer arises from the reaction of carboxylic acid and an alcohol and loss of water molecules.

precipitation

explanation:

when it goes from cloud to rain/back to earth in the form of rain

indium, and thallium have three electrons i think