bonding, structure and properties of matter

• A substance that has a high melting point will have strong intermolecular forces between particles
• if it loses an electron it will have a positive charge and if it gains an electron it will have a negative charge

  
• ionic compounds have a giant ionic lattice structure so they have strong electrostatic forces of attraction
• ionic compounds have high melting and boiling points due to the strong bonds
• when ionic compounds melt the ions are free to move so they will carry electric charge
• when non metals bond together they share pairs of electrons to make covalent bonds
• they only share electrons in their outer shells

  
• these do not show how the atom is arranged in space or the relative sizes

  A) dot and cross

  
• these do not show the covalent bonds or the 3D structure

  A) displayed formula

  
• the 3D models do not show where the electrons in the bonds have come from

  
• simple molecular substances are soluble in water and have low melting and boiling points
• simple molecular substances do not conduct electricity as there are no free electrons or ions
• polymers are solid at room temperature as they require lots of energy to break the bonds
• ionic compounds are brittle and hard due to strong electrostatic forces between oppositely charged ions
• metals are good conductors because their outer shell electrons can move freely through the lattice
• giant covalent structures have high melting and boiling points as they have very strong covalent bonds
• giant covalent structures do not conduct electricity
• diamond - each carbon atom creates 4 covalent bonds
• graphite - each carbon atom creates 3 covalent bonds, they are in a form of hexagon layers which have 1 delocalised electron
• silicon - also known as sand, one grain of sand is one giant structure of silicon and oxygen
• diamond is very hard, it has a high BP and MP and doesn't have a free electron to carry a charge
• in graphite the layers are held together weakly which makes graphite soft
• graphite has a high MP and conducts electricity and thermal energy due to the delocalised electron
• there are strong forces of electro static attraction

  elements and alloys

  A) metallic bonding

  
• the delocalised electrons in metallic bonding make them good conductors of electricity and heat
• metallic bonds need lots of energy to break down
• metallic bonds can slide over eachother making them malleable
• alloys often contain a mixture of 2 or more metals
• alloys are harder as the different sized atoms will prevent the layers from sliding over eachother
• aqueous means dissolved in water