Three elements have the electron configurations $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6}$, $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2}$, and $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{1}$. The first ionization energies of these elements (not in the same order) are $0.419,0.735$, and $1.527 \mathrm{MJ} / \mathrm{mol}$. The atomic radii are $1.60,0.98$, and $2.35 \AA$. Identify the three elements, and match the appropriate values of ionization energy and atomic radius to each configuration.
