Science lesson plan · 9th grade (Year 10 in England) · 45 minutes
Electron shells and the periodic table
Atoms, elements and the periodic table
CCSS NGSS.HS-PS1-1England: KS4 Combined Science: Atomic structure and the periodic table
Objective and success criteria
Students will: Electron shells and the periodic table.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Atomic number, mass number and isotopes
Leads to: Ionic, covalent and metallic bonding; Predict ion charges from the periodic table
Materials: Periodic tables, Atom model kits, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Atomic number, mass number and isotopes). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- An atom of lithium is written ⁷₃Li (mass number 7, atomic number 3). How many electrons does it have? → 3Prompt: Atomic number = number of protons (= electrons in a neutral atom).
- Carbon has atomic number 6. How many neutrons are in the isotope carbon-12? → 6Prompt: The number after the name is the mass number.
- A sodium atom loses one electron to become a sodium ion. What is its charge? (+1 / 0 / −1 / +11) → +1Prompt: It now has one more proton than electrons.
Hook · 5 min
- Show the periodic table and ask what patterns students can see before anything is explained.
- Share the objective: Electron shells and the periodic table. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: How many electrons does an atom of neon (atomic number 10) have in its outer shell?
- Step 1: 2,8
- Step 2: So the answer is: 8
- Answer: 8
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- How many electrons does an atom of potassium (atomic number 19) have in its outer shell? → 1Prompt: Fill the shells 2, 8, 8 in order.
- Who arranged the elements in an early periodic table and left gaps for undiscovered elements? (Isaac Newton / Charles Darwin / Marie Curie / Dmitri Mendeleev) → Dmitri MendeleevPrompt: He predicted the properties of gallium and germanium before they were found.
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Why does potassium react more vigorously with water than sodium? (Its outer electron is further from the nucleus, so it is lost more easily / It has fewer protons / It is a non-metal / It has a full outer shell) → Its outer electron is further from the nucleus, so it is lost more easilyPrompt: Potassium has one more shell than sodium.
- How many electrons does an atom of neon (atomic number 10) have in its outer shell? → 8Prompt: Fill the shells 2, 8, 8 in order.
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Atomic number, mass number and isotopes.
- Use concrete materials: periodic tables.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Ionic, covalent and metallic bonding; Predict ion charges from the periodic table.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-9.
Free lesson plan from eurekami.com/lesson-plan-builder