Chemistry
Chemistry
Problem
A PES spectrum for a second-period element displays two prominent peaks: one at 25 eV with a relative height of 2 and another at 15 eV with a relative height of 6. Describe what the 3 : 1 ratio of these peak heights indicates about the number of electrons in the two corresponding subshells.Intuitive explanation
The peak heights in a photoelectron spectrum directly reflect the number of electrons being ionized from each subshell—taller peaks mean more electrons. Here, the 6:2 ratio simplifies to 3:1, telling you that the higher-energy peak (25 eV) corresponds to a subshell with fewer electrons, while the lower-energy peak (15 eV) represents a subshell with three times as many. This ratio is your direct window into electron configuration: matching these counts to the orbital capacities ( holds 2, holds 6) reveals which subshells are occupied.
Intuitive explanation
The peak heights in a photoelectron spectrum directly reflect the number of electrons being ionized from each subshell—taller peaks mean more electrons. Here, the 6:2 ratio simplifies to 3:1, telling you that the higher-energy peak (25 eV) corresponds to a subshell with fewer electrons, while the lower-energy peak (15 eV) represents a subshell with three times as many. This ratio is your direct window into electron configuration: matching these counts to the orbital capacities ( holds 2, holds 6) reveals which subshells are occupied.