1) Moseley's changes to the periodic table were based mainly on what part of the scientific process?
observation of the elements
argumentation among scientists
existing knowledge about mass
competition among scientists
2) Why are the elements fluorine (F), chlorine (Cl), and bromine (Br) all found in the same group within the periodic table?
They all exist as gases at room temperature.
They all react with the noble gases.
They have similar chemical properties.
They are all non-metals that form 1+ ions.