JAMB - Chemistry (2022 - No. 32)
Electrons enter into orbitals in order of increasing energy as exemplified by?
1S\(^2\)2S\(^2\)2PX\(^2\)2py\(^2\)2pz\(^0\)3s\(^0\)
1S\(^2\)2S\(^2\)2PX\(^2\)2py\(^1\)2pz\(^1\)3s\(^0\)
1S\(^2\)2S\(^2\)2PX\(^1\)2py\(^1\)2pz\(^1\)3s\(^1\)
1S\(^2\)2S\(^2\)2PX\(^2\)2py\(^2\)2pz\(^0\)3s\(^1\)
Explication
Shells and subshells are filled in energy level order, so electrons will fill the 2p subshell before the 3s shell.
And the x subshell before the y and z.