2. The first inert gas to be isolated was argon, in 1894. Argon was found to have an atomic weight of slightly less than 40. Which of the following proposed changes to
Mendeleev's original periodic table were supported by the properties of argon?
I. Calcium should no longer be considered one of the alkaline earth metals.
II. Another group of elements should be added to the periodic table.
III. Argons atomic weight is greater than Potassium, thus the periodicity of the elements
should depend on atomic number rather than atomic weight.