The elements in a column of the periodic table * have similar properties
are in the same period
have the same atomic mass
have very similar chemical symbols

have similar properties

Explanation:

Elements in a column of the periodic table have similar chemical properties.

A periodic column is also called a group or family.

Elements in the same group has the same number of valence electrons.

Therefore, they will combine chemically the same way.

This is not so for the periods on the periodic table.

the earth would become to overheated and everything alive on it will eventually die from overheating. plants will eventually die as well, water will evaporate, and it will be nothing but a hot planet without anything living on it.