Write electron configurations

Answer Key - Grade 10 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   The d subshell of an iron atom holds 6 electrons. Following Hund's rule, how many of them are unpaired, Ari?

   4 electrons
2. 2.

   The d subshell of a cobalt atom holds 7 electrons. Following Hund's rule, how many of them are unpaired, Bo?

   3 electrons
3. 3.

   The d subshell of a nickel atom holds 8 electrons. Following Hund's rule, how many of them are unpaired, Esme?

   2 electrons
4. 4.

   Oxygen has 4 electrons in 2p. How many are unpaired, Kira?

   • 0
   • 4
   • 2
5. 5.

   Milo says calcium's last two electrons go into 3d because 3 comes before 4. Agree or disagree?

   • Agree: d comes before s in each shell
   • Disagree: 4s fills before 3d
   • Agree: lower shell numbers fill first
6. 6.

   Noah says the first 3d electron appears at potassium. Agree or disagree?

   • Agree: potassium starts 3d
   • Disagree: it appears at scandium
   • Agree: argon starts 3d
7. 7.

   Pia says shell 3 must be full before any electron enters shell 4. Agree or disagree?

   • Agree: shells fill strictly in order
   • Disagree: 4s fills before 3d
   • Agree: shell 3 holds 8
8. 8.

   Which is scandium's configuration, Ren?

   • [Ar] 4s² 3d¹
   • [Ne] 4s² 3d¹
   • [Ar] 3d³
9. 9.

   Which element of the first transition row has a full 3d subshell, Tala?

   • Iron
   • Zinc
   • Scandium
10. 10.

    Which subshell fills across the first transition row, Zee?

    • 4f
    • 4p
    • 3d