Question

select the correct location on the image. the orbital diagram shows the valence electrons of sulfur, which has 16 electrons. if the electrons were added to the atom one at a time, which would be the last electron to occupy an orbital? image of 3s (paired electrons) and 3p (one paired, two single electrons) orbitals reset next

Explanation:

Step1: Recall electron configuration rules

Sulfur has an atomic number of 16, so its electron configuration is \(1s^2 2s^2 2p^6 3s^2 3p^4\). For the valence electrons (in the 3s and 3p orbitals), the 3s orbital is filled first (2 electrons), then the 3p orbitals. The 3p subshell has three orbitals, and electrons fill them singly first (Hund's rule) before pairing.

Step2: Analyze the 3p orbitals

The 3p subshell has 4 electrons (since valence electrons for S are \(3s^2 3p^4\)). The first three electrons in 3p go into separate orbitals (each with one electron, parallel spins), and the fourth electron will pair with one of the already singly - occupied 3p orbitals. The 3s orbital is already filled (\(3s^2\)). So when adding electrons one at a time, after filling 3s, we fill 3p orbitals. The first three 3p electrons go to each of the three 3p orbitals, and the fourth (last) valence electron will pair with one of the 3p orbitals that already has one electron. Looking at the diagram, the 3p orbitals: one is filled (paired), and two are singly - occupied. The last electron (the 4th in 3p) will go to one of the singly - occupied 3p orbitals to pair. So the last electron to occupy an orbital will be in one of the singly - occupied 3p orbitals (the ones with one electron) to pair. In the given diagram, the 3p orbitals are shown as one with paired electrons, and two with single electrons. The last electron (the 4th in 3p) will be added to one of the singly - occupied 3p orbitals to form a pair. So the correct location is one of the 3p orbitals that has a single electron (to pair with it).

Answer:

The last electron will occupy one of the singly - occupied 3p orbitals (the 3p orbitals with one electron, to pair with the existing electron in that orbital). In the diagram, it is one of the two 3p orbitals that have a single electron (the ones with one arrow, to add a second arrow to pair).