Types Of Substance Flashcards
What structure do ionic compounds have?
Giant ionic lattice. Ions form a closely packed regular lattice which strong electrostatic forces of attraction between oppositely charged charged ions.
What are the properties of ionic compounds?
High melting + boiling point due to strong attraction. Don’t conduct electricity unless melted as ions can’t move. Dissolve easily in water and can carry electric current in solution as ions separate.
What is the structure of substances containing covalent bonds?
Have simple molecular structures + atoms within the molecules are held together by very strong covalent bonds but the forces of attraction between these molecules are very weak
What are the properties of simple molecular substances?
Low melting + boiling points as only need to break the intermolecular forces not covalent bonds. Don’t conduct electricity as no free electrons or ions. Some are soluble /aren’t in water
What are the properties of giant covalent structures?
All atoms are bonded to each other by strong covalent bonds. High MP + BP. Generally don’t contain charged particles so don’t conduct electricity. Aren’t soluble in water.
What is the structure of metallic compounds?
Giant structure, delocalised electrons in outer shell of metal atoms. Strong forces of electrostatic attraction between positive metal ions + negative electrons.
What are the properties of metals?
Most compounds with metallic bonds have high BP/MP. Shiny solids. Aren’t soluble in water. Layers of atoms slide over each other so they’re malleable. Good conductors of electricity + heat due to delocalised electrons.
What are some examples of carbon based giant covalent structures?
Diamond, graphite, graphene.
What is the structure of diamond?
Strong covalent bonds hold the atoms in a rigid lattice structure making diamond really hard - used to strengthen cutting tools. Doesn’t conduct electricity as no free electrons or ions
What is the structure of graphite?
Layers of carbon atoms arranged in hexagons. Free to move over each other so it’s a good lubricating material. Conducts electricity. High MP
Why is graphite used to make electrodes?
Only 3 out of carbons 4 outer electrons are used in bonds so each carbon atom has 1 delocalised electrons to carry charge.
Why is graphite a good lubricant?
Because there’s no covalent bonds between the layers so they’re slippery.
What are fullerenes?
Molecules of carbon shaped like closed tubes or hollow balls.
What are some properties of graphene?
Conduct electricity, tensile strength so can strengthen materials without adding much weight.
Properties of fullerenes
Huge surface area so could help make industrial catalysts
What is C60?
A fullerene that forms a hollow sphere make up of 20 hexagons + 12 pentagons. Stable molecule that forms soft brownish/black crystals.
What are polymers?
Molecules made up of long chains of covalently bonded carbon atoms eg polyethene.
What are the differences between metals + non metals properties?
metals are shiny solids which have high MP, high density and are good conductors of electricity but most non-metals have low BP and are poor conductors of electricity
What are the limitations of 2D models?
Don’t show shape of substance + don’t show sizes of the atoms
What are the limitations of dot and cross diagrams?
Don’t show size of atoms/ions or how they’re arranged
What are the limitations of 3D models?
Only show the outer layer of arrangement of ions on the substance
What are the limitations of ball + stick models?
Make it look like there’s big gaps between atoms. Don’t show correct scales of atoms or ions.
