covalent and metallic bonding Flashcards
define a covalent bond
a shared pair of electrons one from each donor atoms
define covalent bonding
the electrostatic attraction between the nuclei and the bonding pair of electrons which holds the 2 nuclei together
how does length of bond affect strength
shorter bond = stronger bond
define dative covalent bond
shared pair of electrons both from one donor atom
what bonds are broken when a molecular lattice is melted
weak intermolecular forces (not covalent)
what bonds are broken when melting a giant covalent lattice
covalent bonds
define allotrope
2 or more forms of the same element in which the atoms or molecules are arranged in different ways
why is diamond so strong
bonds are covalent and bonding electrons are localised close to the nucleus
why can graphite conduct electricity
delocalised electrons are mobile and move freely across the plane of the sheet
what can be done with graphene
can be rolled into a ball to form a fullerene or into a cylinder to form nanotubes
define metallic bonding
electrostatic attractions between positive metal cations and the delocalised electrons
what does the strength of the metallic bond depend on
number of delocalised electrons
size of the ions
how does delocalised electrons affect strength of bond
greater number means stronger bond
how does size of ions affect strength
smaller ions = stronger bonds
why can metals conduct heat and electricity
delocalised electrons are free to move and carry charge/transfer heat.
