Multiple Choice
How many electrons are present in the second energy level (n = 2) of a neutral lithium atom?
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 potassium (K)?
A
1s^2 2s^2 2p^6 3s^2 3p^6 4s^1
B
1s^2 2s^2 2p^6 3s^2 3p^5 4s^2
C
1s^2 2s^2 2p^6 3s^2 3p^6 4p^1
D
1s^2 2s^2 2p^6 3s^2 3p^6 3d^1
Verified step by step guidance1
Identify the atomic number of potassium (K), which is 19. This means potassium has 19 electrons to arrange in its electron configuration.
Recall the order of filling electron orbitals based on the Aufbau principle: 1s, 2s, 2p, 3s, 3p, 4s, then 3d, and so on.
Fill the orbitals with electrons following the order and the maximum number of electrons each orbital can hold: s orbitals hold 2 electrons, p orbitals hold 6, and d orbitals hold 10.
Write the electron configuration by placing electrons in orbitals until all 19 electrons are accounted for, noting that after filling 3p (which holds 6 electrons), the next electron goes into the 4s orbital.
Verify that the configuration matches the pattern: $1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$, which correctly accounts for all 19 electrons in potassium.
Related Videos
Related Practice
The Electron Configuration practice set
Problem sets built by lead tutorsExpert video explanations