Which of the following is the correct electron configuration for boron (atomic number 5)?

• A. 1s^2 2s^1 2p^1
• B. 1s^2 2s^2 2p^1
• C. 1s^2 2s^2 2p^2
• D. 1s^2 2s^1 2p^2

Answer: (B)

Verified step by step guidance

1. Step 1: Identify the atomic number of boron, which is 5. This means boron has 5 electrons to place in its electron configuration.
2. Step 2: Recall the order in which electron orbitals are filled according to the Aufbau principle: 1s, 2s, then 2p.
3. Step 3: Fill the 1s orbital first with 2 electrons: \$1s^{2}$.
4. Step 4: Next, fill the 2s orbital with 2 electrons: \$2s^{2}$.
5. Step 5: Place the remaining 1 electron in the 2p orbital: \$2p^{1}$. Thus, the electron configuration is \$1s^{2} 2s^{2} 2p^{1}$.