Science lesson plan · 8th grade (Year 9 in England) · 45 minutes
Group 1: the alkali metals and their trend
Atoms, elements and the periodic table
CCSS NGSS.MS-PS1-1CCSS NGSS.HS-PS1-1England: KS3 Chemistry: The periodic tableEngland: GCSE Combined Science: Atomic structure and the periodic table
Objective and success criteria
Students will: Group 1: the alkali metals and their trend.
- 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: The periodic table: groups and periods
Leads to: the next skill in this area.
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 (The periodic table: groups and periods). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Which family does lithium belong to? (alkali metals (group 1) / halogens (group 17, also called group 7) / noble gases (group 18, also called group 0)) → alkali metals (group 1)Prompt: Is it a soft metal, a coloured reactive non-metal, or an unreactive gas?
- Which family does iodine belong to? (alkali metals (group 1) / halogens (group 17, also called group 7) / noble gases (group 18, also called group 0)) → halogens (group 17, also called group 7)Prompt: Is it a soft metal, a coloured reactive non-metal, or an unreactive gas?
- Which family does helium belong to? (alkali metals (group 1) / halogens (group 17, also called group 7) / noble gases (group 18, also called group 0)) → noble gases (group 18, also called group 0)Prompt: Is it a soft metal, a coloured reactive non-metal, or an unreactive gas?
Hook · 5 min
- Show the periodic table and ask what patterns students can see before anything is explained.
- Share the objective: Group 1: the alkali metals and their trend. 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: Complete the word equation: lithium + water → ? + hydrogen
- Step 1: alkali metal + water → metal hydroxide + hydrogen
- Step 2: So the answer is: lithium hydroxide
- Answer: lithium hydroxide
- 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.
- Complete the word equation: sodium + water → ? + hydrogen → sodium hydroxidePrompt: The solution left is alkaline.
- Why does reactivity increase down group 1? (The atoms get smaller / The nucleus loses protons / The outer electron is further from the nucleus, so it is lost more easily / The atoms have more outer electrons) → The outer electron is further from the nucleus, so it is lost more easilyPrompt: All group 1 atoms have one outer electron.
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 reactivity increase down group 1? (The nucleus loses protons / The outer electron is further from the nucleus, so it is lost more easily / The atoms get smaller / The atoms have more outer electrons) → The outer electron is further from the nucleus, so it is lost more easilyPrompt: All group 1 atoms have one outer electron.
- The alkali metals: which statement is NOT true? (Alkali metals react with water to make alkaline solutions. / Group 1 metals are soft enough to cut with a knife. / Alkali metals form ions with a 1+ charge. / Lithium is the most reactive alkali metal.) → Lithium is the most reactive alkali metal.Prompt: Which way does reactivity change down the group?
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: The periodic table: groups and periods.
- 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
- 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-8.
Free lesson plan from eurekami.com/lesson-plan-builder