How do they (elements) usually exist?

Minimum number of physical forms that an element should exist to show allotropy.

How do the winds arise?

How do the representative elements exhibit chemical reactivity?

How are the elements arranged into groups and periods in the modern periodic Table ? Elements in a group posses similar properties , but elements in a period do not show similarites in their properties . Why ?

The common oxidation state exhibited by inner transition elements usually in their compounds is

How do the positions of elements in the periodic table help you to predict its chemical properties ? Explain with and example .

The following salts of II A elements always exist in liquid state

How do fishes swim?