Question

why are ice and steam not called allotropes of water

Answer 1

because here the physical state is different.but no the arrangements of atoms

Answer 2

Explanation:

Allotropism is the property of an element to exist in different forms. Few elements only show this property. Carbon is one of them. It has many allotropes. Diamond, graphite, charcoal, fullerens are all allotropes of carbon element.

Ice and steam are the physical phases of water. Ice is the solid phase of water and steam is the gaseous phase of water.

Physical phases are interconvertible but allotropes are non-interconvertible.

Hence, ice and steam cannot be considered as the allotropes of water.