Mr Cole Chemistry

Electron Configuration Questions

Electron Configuration

Worksheet

First 20 Elements

Draw the electron configurations of the following elements:
1. C 2. Mg 3. He 4. Ar 5. O 6. Ca 7. K 8. Ne 9. H 10. P 11. F 12. S 13. Na 14. Be 15. Al 16. N
Answer
1. C: 1s2 2s2 2p2
2. Mg: 1s2 2s2 2p6 3s2
3. He: 1s2
4. Ar: 1s2 2s2 2p6 3s2 3p6
5. O: 1s2 2s2 2p4
6. Ca: 1s2 2s2 2p6 3s2 3p6 4s2
7. K: 1s2 2s2 2p6 3s2 3p6 4s1
8. Ne: 1s2 2s2 2p6
9. H: 1s1
10. P: 1s2 2s2 2p6 3s2 3p3
11. F: 1s2 2s2 2p5
12. S: 1s2 2s2 2p6 3s2 3p4
13. Na: 1s2 2s2 2p6 3s1
14. Be: 1s2 2s2
15. Al: 1s2 2s2 2p6 3s2 3p1
16. N: 1s2 2s2 2p3

Beyond Calcium (Ca)

Draw the electron configurations of the following elements:
1. Ni 2. Zr 3. Se 4. Br 5. Ti 6. Te 7. Ru 8. V 9. Rh 10. Cr 11. As 12. Rb 13. Kr 14. Ga 15. Cd 16. Sb
Answer
1. Ni: 1s2 2s2 2p6 3s2 3p6 3d8 4s2
2. Zr: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d2 5s2
3. Se: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p4
4. Br: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p5
5. Ti: 1s2 2s2 2p6 3s2 3p6 3d2 4s2
6. Te: [Kr] 4d10 5s2 5p4
7. Ru: [Kr] 4d7 5s1 (or 4d6 5s2)
8. V: 1s2 2s2 2p6 3s2 3p6 3d3 4s2
9. Rh: [Kr] 4d8 5s1
10. Cr: 1s2 2s2 2p6 3s2 3p6 3d5 4s1
11. As: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p3
12. Rb: [Kr] 5s1
13. Kr: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6
14. Ga: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1
15. Cd: [Kr] 4d10 5s2
16. Sb: [Kr] 4d10 5s2 5p3
State two elements that are an exception to the usual rules and write their electron configurations.
Answer
Cu (Copper):
1s2 2s2 2p6 3s2 3p6 3d10 4s1
Cr (Chromium):
1s2 2s2 2p6 3s2 3p6 3d5 4s1

Atoms and Ions

Draw the electron configurations of the following atoms and ions:
1. Li+ 2. S2- 3. Cu+ 4. Fe2+ 5. N3- 6. Al3+ 7. Fe3+ 8. F– 9. Ag+ 10. Cu2+ 11. Mg2+ 12. Br–
Answer
1. Li+: 1s2
2. S2-: 1s2 2s2 2p6 3s2 3p6
3. Cu+: [Ar] 3d10
4. Fe2+: [Ar] 3d6
5. N3-: 1s2 2s2 2p6
6. Al3+: 1s2 2s2 2p6
7. Fe3+: [Ar] 3d5
8. F–: 1s2 2s2 2p6
9. Ag+: [Kr] 4d10
10. Cu2+: [Ar] 3d9
11. Mg2+: 1s2 2s2 2p6
12. Br–: [Ar] 3d10 4s2 4p6 (or [Kr])
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