Which pair of properties describes the elements in Group 18? They have eight valence electrons and are flammable.
They are chemically stable and liquid at room temperature.
They are gaseous at room temperature and chemically stable.
They are magnetic and boil at low temperatures.

Its the third option

They have low boiling points, explaining why they are gases at room temperature.

And the valence shells are full so they are chemically stable.

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