Answer Happy

ALL BUT ONE of the following sentences provide reasonable explanations for the overall trend and the irregularities observed in the second ionization energies (i.e., IE2) of the elements whose cations are shown in the table. Identify the one statement that is INCORRECT. Na Mg AI Sit P+ st CI Art IE [kJ/mol) 4562 1451 1817 1577 1903 2251 2297 2665 O a. The valence shell of Nat is on the 2nd level of energy whereas the valence shell of Mg* is on the third. That means valence electrons in the sodium ion are far less shielded than those of magnesium. Additionally, Na* has a noble gas nfiguration. That is why the IE, of Nat is so much larger than the IE2 of Mg* Ob. For elements in a same row, the effective nuclear charge is inversely proportional to the atomic number. That explains the overall trend we observe when ionization energy decreases as we move to the left in the periodic system Oc. The IEz of Sit is lower than the IE, of Albecause only one of the degenerate orbitals in the p subshell of the silicon ion is partially occupied. That makes this fon unstable, so when this electron is removed, leaving a Si2ion with a complete s subshell the energy requirement is far less than expected. Od. The lower the energy level is, the more energy will be required to remove electrons from the atom. The same applies to the orbitals in the same energy level: electrons in lower-energy orbitals will have higher ionization energy than those in higher-energy orbitals.