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Science

Chemical Bonding

Overview

Students explore why atoms bond together to form compounds, discovering the two main types of chemical bond.

Learning Objective
Students understand the difference between ionic and covalent bonding and can use electron shell diagrams to explain why each type forms.

Resources needed

  • None — or coloured balls to model electron sharing

Lesson stages

0 / 7 done
  1. 1 Recap: noble gases have full outer electron shells and do not react. Other atoms react to achieve full outer shells.
  2. 2 Introduce ionic bonding: one atom gives electrons to another — both achieve full outer shells.
  3. 3 Example: sodium (1 outer electron) gives it to chlorine (7 outer electrons) giving both stable shells giving NaCl (table salt).
  4. 4 Properties of ionic compounds: solid at room temperature, high melting point, conducts electricity when dissolved in water.
  5. 5 Introduce covalent bonding: atoms share electrons rather than transferring them.
  6. 6 Example: two hydrogen atoms share one electron each giving H2 molecule with a shared pair.
  7. 7 Properties of covalent compounds: often gas or liquid at room temperature, low melting point, usually do not conduct electricity.

Tap a step to mark it as done.

Variations

  • Model ionic and covalent bonding using balls representing electrons — physically transfer or share them.
  • Compare sodium chloride (ionic) and water (covalent) — test conductivity and melting point.
  • Introduce metallic bonding: a lattice of positive ions in a sea of delocalised electrons.
More information

Teach: ionic, covalent, bond, electron, transfer, share, compound, lattice. The key distinction: ionic = transfer electrons, covalent = share electrons. Both result in stable full outer shells.

Focus on ionic bonding only using the sodium and chlorine example before introducing covalent bonding.

Can students explain why sodium and chlorine form an ionic bond? Can they describe one property difference between ionic and covalent compounds?

Draw electron shell diagrams in soil. Physical modelling of electron transfer and sharing uses any available objects.

Students often think bonds are physical connections between atoms. Bonds are electrostatic attractions — the result of electrical forces between positive and negative charges or shared electrons.

Chemical bonding explains why substances have the properties they do — their melting points, solubility, conductivity, and reactivity.

Activity details
Secondary Challenging 25 minutes no prep Whole Class, Small Group Indoor & Outdoor
Topics
Chemical Bonding Ionic Bonds Covalent Bonds