Multiple Choice
Which of the following orbital electron configurations is not possible?
2
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 electron configurations represents a potassium atom (K) in an excited state?
A
1s^2 2s^2 2p^6 3s^2 3p^6 3d^1
B
1s^2 2s^2 2p^6 3s^2 3p^6 4s^2
C
1s^2 2s^2 2p^6 3s^2 3p^6 4s^1
D
1s^2 2s^2 2p^6 3s^2 3p^5 4s^2
Verified step by step guidance1
Recall that the ground state electron configuration of potassium (K), which has atomic number 19, fills orbitals in order of increasing energy according to the Aufbau principle.
Write the ground state configuration by filling orbitals: 1s, 2s, 2p, 3s, 3p, and then 4s. This gives the configuration $1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$.
Understand that an excited state occurs when one or more electrons are promoted to a higher energy orbital than the ground state configuration, leaving a lower energy orbital partially filled or empty.
Examine each given configuration to see if it deviates from the ground state by having electrons in higher energy orbitals (like 3d) before lower energy orbitals (like 4s) are fully occupied.
Identify the configuration $1s^2 2s^2 2p^6 3s^2 3p^6 3d^1$ as an excited state because an electron has moved from the 4s orbital to the 3d orbital, which is higher in energy for potassium, indicating excitation.
Related Videos
Related Practice
The Electron Configuration practice set
Problem sets built by lead tutorsExpert video explanations