Key Concepts Flashcards
What are Ionic compounds?
Have regular (ionic) lattice structure. Ions form closely packed regular lattice. Very strong electrostatic forces of attractions between opp charged ions in all directions.
What are the similar properties of ionic compounds?
High melting + boiling points due strong attraction between ions. Large amount energy overcome attraction. Solid ionic compounds don’t conduct electricity. Ions fixed in place and can’t move, whereas in an ionic compound that has melted, its ions are free to move so they can carry an electric current. Many dissolve easily water. Ions separate and are all free to move in solution so they’ll carry electric current.
What are the models that show ionic compounds?
2D representations: (for example, displayed formulas) of molecules are simple. Great showing atoms something contains + how atoms are connected. Don’t show shape of the substance and don’t give any idea about size of atoms.
Dot and cross diagrams: useful for showing how compounds/molecules formed + where electrons in bonds or ions came from. Don’t show size of atoms/ions or how they’re arranged.
3D models: of ionic solids show arrangement of ions, but only show outer layer of substance.
Ball and stick models: show atoms in substance are connected. Can draw them/make them with plastic molecular model kits/computer models. Help visualise structure as show shape of lattice or molecule in 3D. +Realistic than 2D drawings however still misleading. make it look like there are big gaps between atoms in reality this is where electron clouds interact. Don’t show correct scales of atoms/ions. Atoms/ions are different sizes but it isn’t shown well.
