• Quick retrieval from earlier learning (Electron shells and the periodic table). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. 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.
2. 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 a full outer shell / It is a non-metal / It has fewer protons) → Its outer electron is further from the nucleus, so it is lost more easilyPrompt: Potassium has one more shell than sodium.
3. How many electrons does an atom of aluminium (aluminum) (atomic number 13) have in its outer shell? → 3Prompt: Fill the shells 2, 8, 8 in order.

• Show the periodic table and ask what patterns students can see before anything is explained.
• Share the objective: Ionic, covalent and metallic bonding. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: What type of bonding is in potassium bromide (KBr)?
• Step 1: Ionic bonds form between metals and non-metals when electrons are transferred.
• Step 2: So the answer is: ionic
• Answer: ionic
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. What type of bonding is in ammonia (NH₃)? (ionic / covalent / metallic) → covalentPrompt: Is it metal + non-metal, only non-metals, or only a metal?
2. What is the charge on a potassium ion? (+1 / +3 / +2 / −1) → +1Prompt: Metals lose their outer electrons and become positive.

• 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.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. Bonding: which statement is NOT true? (Diamond is a giant covalent structure and is very hard. / Simple covalent substances such as water have low melting and boiling points. / In covalent bonds, electrons are transferred from one atom to another. / Ionic compounds have high melting points.) → In covalent bonds, electrons are transferred from one atom to another.Prompt: Can ions move in a solid?
2. What type of bonding is in sodium chloride (NaCl)? (ionic / covalent / metallic) → ionicPrompt: Is it metal + non-metal, only non-metals, or only a metal?

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-10.