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Worksheet: Energies of Atomic Orbitals


Which of the following statements is false?

  • AElectrons are usually added to the 4s subshell before the 3d subshell.
  • BElectrons fill subshells of equal 𝑛 in order of increasing 𝑙 .
  • CElectrons are usually removed from the 4s subshell before the 3d subshell.
  • DElectrons fill subshells in order of increasing 𝑛 .
  • EThe energy difference between the 3d and 4s subshells is sometimes less than the pairing energy of the 4s subshell.


Atoms of P a , U , N p , C m and L r contain one electron in the 6d subshell and two electrons in the 7s subshell. A 6d0 configuration is produced if the d electron is promoted to a 5f or higher energy orbital. In which of these atoms does changing from a 6d1 to a 6d0 configuration produce the greatest increase in pairing energy?

  • A U
  • B P a
  • C N p
  • D C m
  • E L r