Classification of Elements and Periodicity in Properties — Prelims Questions

Which of the following orders of atomic radii is correct?

Which of the following elements has the highest first ionization enthalpy?

Which of the following is the correct order of ionic radii for the isoelectronic species $N^{3-}, O^{2-}, F^{-}, Na^{+}$?

Which of the following statements regarding electron gain enthalpy is incorrect?

Which of the following elements has the highest electronegativity?

Which of the following pairs of elements would you expect to have similar chemical properties?

Which of the following statements is correct regarding the metallic character of elements?