structure and bonding Flashcards
what holds ions in a a lattice tightly in giant ionic compounds
strong electrostatic forces of attractions between the oppositely charged ions (which act in all directions)
why do giant ionic compounds have a high melting and boiling point
as they have strong electrostatic forces of attraction acting in all directions, this means it would require lots of energy to overcome these forces and separate the ions in their lattice making them have high melting and boiling points
why can giant ionic compounds conduct electricity when the electrostatic forces are over come
as when the ions are separated from the lattice the IONS become mobile and are free to move, these freely moving ions can carry electric charge
why cant ionic solids conduct electricity
as the ions are in fixed positions and can only vibrate as they cannot move
properties of ionic compound’s
- high melting point and boiling point
- can conduct electricity
cons of 2d ball and stick model
do not represent the shape of the molecule or the correct angles the atoms are bonded at
pro of dot and cross model
- allows you to see which electron comes from which atom
- shows that electrons are found in-between atoms
cons of dot and cross model
- not all electrons look the same
- electrons are not in fixed positions as they are constantly moving
why do simple molecules have low boiling and melting points
as they have weak intermolecular forces this means that it does not require lots of energy to overcome these forces
why do larger molecules have a higher melting point than smaller molecules
as when a molecule increase their intermolecular forces become stronger so they require more energy to overcome these forces (so id you go down a group on non metals the melting and boiling point increases)
why cant simple molecules conduct electricity
as they do not have charged ions or delocalised electrons to carry the electrical charge (but they can conduct electricity when reacted in water as they form aqueous ions)
what is the lattice in simple molecular held by
strong covalent bonds
why are metals malleable
as metal are arranged in layers, these layers can easily slide over each other making the metal very malleable
why do metals have a high melting and boiling points
as they have strong metallic bonds between the oppositely charged ions, this means it would require lots of energy to overcome these forces
why can metals conduct electricity and thermal energy
as they have delocalised electrons which can move freely throughout the structure and carry electrical and thermal charge
what is an allotrope
an allotrope is two substances made up of the same element at the same physical state but have different structures
what are fullerenes
fullerenes are allotropes of carbon made by bending sheets of graphene into hollow like structures
what are cylindrical fullerenes called and what is there ratio
nanotubes
they have a high length to diameter ratio
what are cylindrical fullerenes called and what is there ratio
nanotubes
they have a high length to diameter ratio
carbon nanotube properties
- good thermal and electrical conductors as they have delocalised electrons
- high tensile strength