Physical 1: Bonding Flashcards
what is ionic bonding?
strong electrostatic forces of attraction between oppositely charged ions held in a lattice
give an example of an ionically bonded substance
NaCl
how high are ionically bonded substances’ boiling point and melting point?
high - takes lots of energy to break strong electrostatic forces of attraction between oppositely charged ions
do ionic compounds conduct electricity?
yes, when molten/in solution as the ions are free to move and carry charge
they don’t when solid
what is simple molecular covalent bonding?
strong covalent bonds between atoms, weak van der waals forces of attraction between molecules
are there any lone electrons in simple covalent bonding?
no - all involved in bonding
can simple molecular covalent molecules conduct electricity?
no - all electrons used in bonding and aren’t free to move
do simple molecular substances have a high/low mpt and bpt?
low - weak vdw forces of attraction between molecules that don’t take much energy to overcome (these are overcome rather than covalent bonds)
describe macromolecular covalent bonding
lattice of many atoms held together by strong covalent bonds
do substances with macromolecular covalent bonds have high/low mpt and bpts?
high, as it takes a lot of energy to overcome many strong covalent bonds
do substances with macromolecular covalent bonds conduct electricity?
most don’t as all electrons are used in bonding
describe the structure of diamond
3D tetrahedral structure of C atoms, with each C atom bonded to four others
describe the structure of graphite
- macromolecular covalent
- each C atom is bonded to 3 others, so it is in layers
- weak vdws between layers mean they can slide over each other —- soft and slippery
- one electron from each carbon is delocalised and can carry charge —- conducts electricity
describe metallic bonding
- lattice of positive metal ions strongly attracted to a sea of delocalised electrons
- layers can slide over each other —- malleable
do metallic compounds have high/low bpt and mpt?
high as strong forces of attraction between positive metal ions and negatively charged sea of delocalised electrons