Which is not a ground state electron configuration?
A. 1s2
B. 1s2 2p1
C. 1s2 2s2
D. 1s2 2s2 2p1
To determine which electron configuration is not a ground state configuration, we need to understand what ground state means.
The ground state electron configuration represents the lowest energy arrangement of electrons within an atom. Electrons occupy the lowest available energy levels and orbitals before moving to higher energy levels.
Let's analyze each option to identify the one that is not a ground state electron configuration:
A. 1s2: This represents the electron configuration of helium, which is the ground state for helium.
B. 1s2 2p1: This represents the electron configuration for boron, which is the ground state for boron.
C. 1s2 2s2: This represents the electron configuration for beryllium, which is the ground state for beryllium.
D. 1s2 2s2 2p1: This represents the electron configuration for nitrogen, not carbon. The ground state electron configuration for carbon is 1s2 2s2.
Therefore, option D (1s2 2s2 2p1) is not the ground state electron configuration.