Ionic compounds Chemistry GCSE

Ionic Compounds

• Ionic compounds have a regular lattice structure
• -Ions form a closely packed regular lattice. Very strong electrostatic forces of attraction between oppositely charged ion in all directions.
• Ionic Compounds all have similar properties
• -High melting & boiling points due to strong attraction between ions. Takes a lot of energy to overcome this attraction
• -Solid ionic compounds don't conduct electricity because ions are fixed in one place. When ionic compound is melted ions are free to move= will carry electric current.
• -Many also dissolve in water. Ions separate free to move in solution carry electric current

Folie 2

• Models that show structures have some limintations
• 1)2D representations of molecules=simple, great at showing what atoms contain, and how they're connected. Don't show the shape of the substance don't give an idea about the size of the atom
• 2)Dot and cross diagram-useful for showing how compounds/molecules are formed & where the electrons in the bonds or ions came from. Don't show anything about size of the atoms or ions or how they're arranged.
• 3)3D models- show arrangement of ions, only show outer layer of substance
• -Ball and stick models show how atoms in a substance are connected, can draw or make
• -Great helping visualise structure, as they know same of lattice or molecule in 3D.
• -More realistic than 2D still a bit misleading. Make it look like there's big gaps between the atoms reality this is where electron clouds interact.
• -Show correct scales of atoms or ions. Atoms and ions are different sizes this isn't shown well in ball and stick models