Textbook Problem

hree elements have the electron configurations $\text{1}{s}^{\text{2}}\text{2}{s}^{\text{2}}\text{2}{p}^{\text{6}}\text{3}{s}^{\text{2}},\text{ 1}{s}^{\text{2}}\text{2}{s}^{\text{2}}\text{2}{p}^{\text{6}}\text{3}{s}^{\text{2}}\text{3}{p}^{\text{4}},\text{ and 1}{s}^{\text{2}}\text{2}{s}^{\text{2}}\text{2}{p}^{\text{6}}\text{3}{s}^{\text{2}}\text{3}{p}^{\text{2}}$ . The first ionization energies of these elements (not in the same order) are $0.\text{59}0,0.\text{999}$ . and $0.\text{738 MJ}/\text{mol}$ . The atomic radii are $\text{1}0\text{4}.\text{ 16}0$ , and $\text{197 pm}$ . Identify the three elements, and match the appropriate values of ionization energy and atomic radius to each configuration. Complete the following table with the correct information.

l>

Electron Configuration

td>Element Symbol

td>First Ionization Energy (MJmol)

td>Atomic Radius PM

td>

msp;  ${\text{1s}}^{\text{2}}2s^{2}2p^{6}3s^2$

msp;  $1s^{2}2s^{2}2p^{5}3s^{2}3p^4$

msp;  $1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}4s^2$