Answer:
A. 1s²2s²
B. 1s²
C. 1s²
D. 1s²2s²2p⁶
Explanation:
The valency electron is the outer electron of an element. The valency electron resides in the outermost region of the shell.
Using the general configuration for the first 20 elements 2 8 8 2 the valency electrons can be identified.
A. 1s²2s²2p⁶3s² . The valency electron here are 2p⁶ and 3s² . Removing the valency electron we have 1s²2s²
B. 1s² 2s² 2p⁶. After removing the valency electron the configuration will be 1s².
C.1s²2s². After removing the valency electron the configuration will be 1s²
D.1s²2s²2p⁶3s¹. Removing the valency electron the electron configuration will be 1s²2s²2p⁶