Chemicals in a column, or "group" have similar chemical properties.
They have the same Valency
Elements in a given column have the same number of valence electrons and hence the similar properties.
All of the elements in column 18 of the periodic table are noble gases. This means their outer electron shells are completely full and in most cases are inert.
they all have the same electrons.
The noble gases, column 18 in the most common modern periodic table.
Elements in same column have equal number of valence electrons. so they possess similar chemical properties.
they are all in the same group (column) in the Periodic Table
Elements in a given group have the same number of valence electrons and hence they have similar properties.
valance, although there is lot of variation here as well.
NOTHIN !
The periodic table contain all chemical elements, placed in a rational order.
The elements in each column of the periodic table have the same number of valence electrons. None of the other characteristics listed in the question is common to all these elements.