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.

   Nitrogen has 3 electrons in 2p. How are they placed, Jun?

   • The three together in one orbital
   • Two in one orbital, one in another
   • One in each of the 3 orbitals
5. 5.

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

   • 4
   • 0
   • 2
6. 6.

   Why do electrons fill orbitals singly before pairing, Luz?

   • Single electrons are heavier
   • Pairs are forbidden
   • They repel less when spread out
7. 7.

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

   • Agree: argon starts 3d
   • Disagree: it appears at scandium
   • Agree: potassium starts 3d
8. 8.

   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
9. 9.

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

   • Zinc
   • Iron
   • Scandium
10. 10.

    Which subshell fills across the first transition row, Zee?

    • 4p
    • 4f
    • 3d