Electron Configuration Worksheet with Answers (Grade 11 Chemistry)

This free electron configuration worksheet gives Grade 11 students 33 practice questions, from writing a simple configuration for carbon to explaining why chromium and copper break the rules.

It covers full configurations, noble-gas shorthand, orbital box diagrams, ions, error spotting and exceptions. A complete answer key is included, so students can check their own work.

• Grade 11 Chemistry
• 33 marks
• 35–45 minutes
• Answer key included

What's in This Electron Configuration Worksheet

The questions build from basic to challenging, so the same sheet works for a first lesson, homework or unit review.

Part	Skill practised	Questions
A	Full electron configurations (C to Br)	8
B	Noble-gas shorthand	6
C	Orbital (box) diagrams and unpaired electrons	4
D	Configurations of ions and isoelectronic species	5
E	Identify the element from its configuration	4
F	Spot the mistake (rule-breaking configurations)	4
G	Challenge: chromium and copper exceptions	2

Every part matches the Ontario Grade 11 chemistry curriculum expectations for atomic structure in the Matter, Chemical Trends and Chemical Bonding unit. The content is also standard for first-year chemistry courses elsewhere.

The Three Rules Behind Every Electron Configuration

Students who understand these three rules rarely get a configuration wrong. The electron configuration worksheet prints them in a quick-reference box at the top of page 1.

For a deeper look at the theory, the electron configuration overview on Wikipedia covers the quantum-mechanics background. An interactive table like Ptable shows the configuration of every element.

How to Write an Electron Configuration in 4 Steps

Here is the method students use on every question in this electron configuration worksheet. The example is sulfur.

1. Find the atomic number. Sulfur is element 16, so a neutral atom has 16 electrons.
2. Fill sublevels in Aufbau order. Use 1s, 2s, 2p, 3s, 3p and stop when you reach 16 electrons.
3. Write each sublevel with a superscript. Sulfur is 1s² 2s² 2p⁶ 3s² 3p⁴.
4. Check the total. 2 + 2 + 6 + 2 + 4 = 16. Every correct answer should add up to the atomic number, or to the electron count for an ion.

For shorthand, swap the core for the previous noble gas. Sulfur becomes [Ne] 3s² 3p⁴. If students need help locating elements, our guide on how to read the periodic table explains groups and periods.

Electron Configuration Practice Questions

These are the same questions that appear in the electron configuration worksheet PDF. Students can work on screen and open each answer box to check their work as they go.

Part A – Full Electron Configurations

Write the complete electron configuration for each element.

1. Carbon (C)
2. Fluorine (F)
3. Aluminum (Al)
4. Sulfur (S)
5. Argon (Ar)
6. Potassium (K)
7. Iron (Fe)
8. Bromine (Br)

Part B – Noble-Gas Shorthand

Write each configuration using the noble-gas core.

9. Silicon (Si)
10. Calcium (Ca)
11. Manganese (Mn)
12. Zinc (Zn)
13. Selenium (Se)
14. Strontium (Sr)

Part C – Orbital Diagrams

Draw the orbital (box) diagram, then count the unpaired electrons.

15. Nitrogen (N)
16. Oxygen (O)
17. Phosphorus (P)
18. Iron (Fe), valence electrons only (4s and 3d)

Part D – Ions

Remember that cations lose electrons and anions gain them.

19. Na⁺
20. O²⁻
21. Cl⁻
22. Ca²⁺
23. Which of these ions are isoelectronic with argon?

Part E – Name That Element

24. 1s² 2s² 2p⁶ 3s¹
25. [Ne] 3s² 3p⁵
26. [Ar] 4s² 3d²
27. [Kr] 5s² 4d¹⁰ 5p²

Part F – Spot the Mistake

Name the rule each student broke and write the correct version.

28. Sodium written as 1s² 2s² 2p⁷
29. Carbon written as 1s² 2s³ 2p¹
30. Titanium written as [Ne] 3s² 3p⁶ 3d²
31. Nitrogen's 2p sublevel drawn as ↑↓↑

Part G – Challenge: The Exceptions

32. Write the actual configurations of chromium (Cr) and copper (Cu) in noble-gas shorthand.
33. Explain why these two elements break the Aufbau pattern.

Electron Configuration Worksheet Answer Key

Open each part to check answers to the electron configuration worksheet. The printable key is on pages 3–4 of the PDF.

Part A answers (Q1–8)

1. 1s² 2s² 2p²
2. 1s² 2s² 2p⁵
3. 1s² 2s² 2p⁶ 3s² 3p¹
4. 1s² 2s² 2p⁶ 3s² 3p⁴
5. 1s² 2s² 2p⁶ 3s² 3p⁶
6. 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
7. 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
8. 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵

Part B answers (Q9–14)

9. [Ne] 3s² 3p²
10. [Ar] 4s²
11. [Ar] 4s² 3d⁵
12. [Ar] 4s² 3d¹⁰
13. [Ar] 4s² 3d¹⁰ 4p⁴
14. [Kr] 5s²

Part C answers (Q15–18)

15. N: ↑↓1s↑↓2s↑↑↑2p 3 unpaired
16. O: ↑↓1s↑↓2s↑↓↑↑2p 2 unpaired
17. P: ↑↓1s↑↓2s↑↓↑↓↑↓2p↑↓3s↑↑↑3p 3 unpaired
18. Fe: ↑↓4s↑↓↑↑↑↑3d 4 unpaired

Part D answers (Q19–23)

19. 1s² 2s² 2p⁶
20. 1s² 2s² 2p⁶
21. 1s² 2s² 2p⁶ 3s² 3p⁶
22. 1s² 2s² 2p⁶ 3s² 3p⁶
23. Cl⁻ and Ca²⁺, which both have 18 electrons like argon

Part E answers (Q24–27)

24. Sodium (Na)
25. Chlorine (Cl)
26. Titanium (Ti)
27. Tin (Sn)

Part F answers (Q28–31)

28. A p sublevel holds only 6 electrons. Correct: 1s² 2s² 2p⁶ 3s¹
29. Pauli: an s orbital holds only 2 electrons. Correct: 1s² 2s² 2p²
30. Aufbau: 4s fills before 3d. Correct: [Ar] 4s² 3d²
31. Hund's rule: fill each orbital singly before pairing. Correct: one ↑ in each of the three 2p boxes.

Part G answers (Q32–33)

32. Cr: [Ar] 4s¹ 3d⁵ · Cu: [Ar] 4s¹ 3d¹⁰
33. One 4s electron moves into 3d because a half-filled (d⁵) or completely filled (d¹⁰) d sublevel is lower in energy and more stable.

5 Common Mistakes Students Make

These come up every year in Grade 11 chemistry, and Part F of the electron configuration worksheet targets most of them directly.

1. Filling 3d before 4s. The Aufbau order puts 4s first, even though 3 is a smaller number than 4.
2. Overfilling a sublevel. Writing 2p⁷ or 3d¹¹ means the electrons belong in the next sublevel.
3. Pairing too early in orbital diagrams. Hund's rule says to spread out first. Oxygen's 2p is ↑↓ ↑ ↑, not ↑↓ ↑↓ ⬜.
4. Getting ions backwards. A positive charge means electrons were lost, so Na⁺ has 10 electrons, not 12.
5. Using the wrong noble gas. The core is always the noble gas from the row above the element.

How to Use This Electron Configuration Worksheet in Class

As a teacher, I use the sheet in three ways depending on where students are in the unit:

• Lesson practice: Assign Parts A–C right after introducing the Aufbau principle. They take about 20 minutes.
• Homework: Send Parts D–G home. The spot-the-mistake questions show quickly who understands the rules and who is only memorizing patterns.
• Unit review: Use the whole sheet as a timed review, then follow up with an online quiz for instant feedback.

To check mastery, pair this worksheet with our electron configuration quiz (20 auto-graded questions) or the periodic trends quiz, which builds directly on configurations.

Frequently Asked Questions

Is this electron configuration worksheet free?

Yes. The electron configuration worksheet and answer key are free to download and print, and you don't need an account.

What grade is it for?

It is written for Grade 11 chemistry. It also works for any introductory high school or first-year college chemistry course.

Why does 4s fill before 3d?

While the sublevels are filling in a neutral atom, 4s is slightly lower in energy than 3d, so the Aufbau principle places electrons there first.

Why are chromium and copper exceptions?

A half-filled d⁵ or completely filled d¹⁰ sublevel is extra stable, so one 4s electron moves into 3d. Part G asks students to explain this.

How long does the worksheet take?

Most students finish all 33 questions in 35–45 minutes.

More Free Grade 11 Chemistry Resources

• Lewis Structures WorksheetNext step after configurations
• Electron Configuration Practice Quiz20 more auto-graded questions
• Ionic vs Covalent Bonding QuizBonding unit review
• Free Chemistry CalculatorsMolar mass, moles and more
• All Grade 11 ResourcesWorksheets and quizzes

Ready to practise? Download the free electron configuration worksheet PDF (use the Download button above), print it double-sided, and keep the answer key pages for marking.