Multiple Choice
Which of the following electron configurations represents an atom of calcium (atomic number 20) in an excited state?
3
views
10. Periodic Properties of the Elements
The Electron Configuration
Struggling with General Chemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Which of the following is the correct electron configuration for boron (B)?
A
1s^2 2s^2 2p^1
B
1s^2 2s^1 2p^2
C
1s^2 2s^1 2p^3
D
1s^2 2s^2 2p^3
Verified step by step guidance1
Step 1: Identify the atomic number of boron (B), which is 5. This means boron has 5 electrons to place in its electron configuration.
Step 2: Recall the order in which electron orbitals are filled according to the Aufbau principle: 1s, 2s, then 2p orbitals.
Step 3: Fill the 1s orbital first with 2 electrons: $1s^2$.
Step 4: Next, fill the 2s orbital with 2 electrons: $2s^2$.
Step 5: Place the remaining 1 electron in the 2p orbital: $2p^1$. Thus, the electron configuration is $1s^2 2s^2 2p^1$.
Related Videos
Related Practice
The Electron Configuration practice set
Problem sets built by lead tutorsExpert video explanations