Periodic table has columns {chemical group}|. Periodic table has 18 columns, one for each orbital.
Leftmost column or 1A column has soft metals {alkali metal} with low densities and melting points.
Second-from-left column or 2A column has harder, higher-density, and higher-melting-point metals {alkaline earth metal}.
Third-from-right column or 6A column has reactive elements {chalcogen} with slight colors.
Second-from-right column or 7A column has colorful and highly reactive gases, liquids, and solids {halogen}|.
Rightmost column or 8A column has inert colorless gases {noble gas}|.
5-Physics-Matter-Atom-Periodic Table
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Date Modified: 2022.0225