Looking at the diagram, we see electron orbitals arranged by increasing energy (from bottom to top). The arrows represent electrons in those orbitals.
Let’s count how many electrons are shown:
- 1s orbital: 2 electrons (one up arrow, one down arrow) → full
- 2s orbital: 2 electrons → full
- 2p orbitals: There are three boxes for 2p. We see:
- First box: ↑↓ (2 electrons)
- Second box: ↑ (1 electron)
- Third box: ↑ (1 electron)
→ Total in 2p: 4 electrons
So total electrons = 2 (1s) + 2 (2s) + 4 (2p) =
8 electrons
Now, let’s think about what element has 8 electrons when neutral — that would be oxygen (atomic number 8).
But wait — is this the ground state configuration? Let’s check the rules:
Hund’s Rule says: Electrons fill degenerate orbitals (like the three 2p orbitals) singly first, with parallel spins, before pairing up.
In the 2p subshell here, we have 4 electrons. That means:
- First 3 electrons go into each of the three 2p orbitals, all with same spin (↑ ↑ ↑)
- The 4th electron pairs up in the first orbital → so it should be ↑↓ ↑ ↑
That’s exactly what’s drawn! So yes, this is a valid ground-state configuration for an atom with 8 electrons.
Therefore, the element is Oxygen.
Final Answer:
Oxygen
Parent Tip: Review the logic above to help your child master the concept of aufbau diagram worksheet.
