Electron affinity Original Scenario-Based Download PDF

Questions

1. 1.

   Deep within the orbital research cruiser Astraea, an exochemist tests isolated gaseous atoms of three unidentified Period 3 elements—designated X, Y, and Z—to power an ion-thruster battery by capturing free electrons. Laboratory telemetry reveals that atom X possesses an electron configuration ending in $3s^2 3p^3$, atom Y ends in $3s^2 3p^4$, and atom Z ends in $3s^2 3p^5$. Which statement correctly compares and explains the first electron affinities of these elements?

   • A) Element X releases more energy upon electron capture than element Y because half-filled subshells attract additional electrons with greater force.
   • B) Element Z has the most exothermic electron affinity, while element X has a less exothermic electron affinity than element Y due to spin-pairing repulsion in a half-filled $3p$ subshell.
   • C) Electron affinity increases strictly and monotonically from X to Y to Z across the period because effective nuclear charge rises without any electronic interferences.
   • D) Element Y has a less exothermic electron affinity than element X because adding an electron to Y disrupts an exceptionally stable fully paired orbital set.