bonding (physical) Flashcards
what is ionic bonding
strong electrostatic force between oppositely charged ions
give an example of an ionically bonded substance
sodium chloride (NaCl)
how high are ionically bonded substances’ boiling and melting points? why?
very high because it takes a lot of energy to break electrostatic forces between oppositely charged ions
do ionic compounds conduct electricity? why?
yes when molten/dissolved in a solution because they are free to move around and hold a charge. they do not conduct electricity when solid
what is simple molecular covalent bonding?
strong covalent bonds between atoms, weak van der waals forces between molecules
are there any lone electrons in simple covalent bonding
no
can simple covalent bonds conduct electricity? why?
no because all of the electrons are used in bonding and arent free to move
do simple molecular covalent substances have high or low boiling and melting points? why?
low because there are weak van de Waals forces that dont need much energy to overcome
describe macromolecular covalent bonding
lattice of many atoms held together by strong covalent bonds
do substances with macromolecular covalent bonds have high or low melting and boiling points? why?
high because it takes a lot of energy to overcome lots of covalent bonds
do substances with macromolecular covalent bonds conduct electricity? why?
most of them dont as electrons are all used in bonding
graphite does as there is a delocalised electron from each carbon free to carry charge
describe the structure of diamond
tetrahedral 3D structure of carbon atoms, each bonded to 4 other carbon atoms
describe the structure of graphite
each carbon atom is bonded to 3 other carbons so it is in layers.
there are weak van de waals forces in between layers so that they can easily slide over eachother.
one electron from each carbon is delocalised so can conduct electricity
describe metallic bonding
lattice of positive metal ions attracted to a sea of delocalised electrons
layers can also slide over eachother meaning they are malleable
do metallic compounds have low or high melting and boiling points? why?
high because there are strong forces of attraction between metal ions and negatively charged sea of delocalised electrons
do metallic compounds conduct electricity? why?
yes because there are delocalised electrons free to carry charge