Ionic or covalent? Modelling chemical bonds
Look at which elements each compound contains, model how their electrons are transferred or shared, and sort the compounds into ionic and covalent.
Core concept
Ionic bonds form when a metal transfers electrons to a non-metal; covalent bonds form when non-metal atoms share electrons
Topic: Chemical bonding
Atoms bond to get a full outer shell of electrons. When a metal meets a non-metal, the metal atom gives its outer electrons to the non-metal atom. The metal becomes a positive ion and the non-metal a negative ion, and the opposite charges attract: an ionic bond. Ionic compounds have high melting points and conduct electricity when molten or dissolve: To mix into a liquid so completely that you can no longer see the pieces. All key words. When non-metal atoms bond, neither gives up electrons; they share pairs of electrons instead: a covalent bond. Covalent substances made of small molecules usually have low melting points and do not conduct.
What you will learn
- Explain how ionic and covalent bonds form.
- Predict the type of bonding from the elements in a compound.
- Link the type of bonding to properties such as melting point and conductivity.
Before you start
- Know the arrangement of electrons in shells for the first 20 elements.
Materials
- Electron shell diagram cards
Equipment
- None for the virtual lab
Procedure
- Choose a compound card and check which elements it contains: metal and non-metal, or only non-metals?
- Model its electrons: are they transferred or shared?
- Place each card in the ionic or covalent group.