Which of the following groups of elements have properties that are most similar?

Which of the following pairs of elements have similar properties-

Which of the following pair of elements has similar properties ?

Which pair of elements have chemical propeties that are the most similar ?

Which of the following pair of group 13 elements have similar atomic radius

Identify dobereiner's traids from the following group of elements having similar chemical properties : Be(9.0),Mg(24.3),Ca(40.1)

Which of the following elements exhibits the most basic properties?

Identify Dobereiner's triads from the following groups of elements having similar chemical properties. Be(9.0), Mg(24.3), Ca(40.1)