Which is the correct ground-state electron configuration for aluminum (Al)?

• A. $1s^{2}2s^{2}2p^{5}3s^{2}3p^2$
• B. $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$
• C. $1s^{2}2s^{2}2p^{6}3s^{1}3p^2$
• D. $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$

Answer: (D)

Verified step by step guidance

1. Step 1: Determine the atomic number of aluminum (Al), which tells you the total number of electrons. Aluminum has an atomic number of 13, so it has 13 electrons in its neutral ground state.
2. Step 2: Recall the order in which electron orbitals are filled according to the Aufbau principle: 1s, 2s, 2p, 3s, then 3p. Electrons fill the lowest energy orbitals first.
3. Step 3: Fill the orbitals with electrons following the order and the maximum number of electrons each orbital can hold: 1s can hold 2, 2s can hold 2, 2p can hold 6, 3s can hold 2, and 3p can hold 6.
4. Step 4: Assign the 13 electrons to the orbitals in order: 2 electrons in 1s, 2 electrons in 2s, 6 electrons in 2p, 2 electrons in 3s, and the remaining electrons in 3p.
5. Step 5: Write the electron configuration using the notation \$1\,s^{2} 2\,s^{2} 2\,p^{6} 3\,s^{2} 3\,p^{1}$, which represents the ground-state electron configuration for aluminum.