structure and bonding Flashcards
what is monatomic bonding
noble gases exist as single atoms - they are monatomic
what is metallic bonding
electrostatic force of attraction between positive metal centres and delocalised electrons
what is covalent molecular bonding
electrostatic force of attraction between 2 positive nuclei and a pair of electrons
what are odd examples of covalent molecular bonding
phosphorus (P4)
sulfur (S8)
buckminster fullerene (c60)
what is covalent network bonding
only boron, silicon and carbon can do this
what is ionic bonding
the electrostatic force of attraction between positive and negative ions
what is pure covalent
- sometimes called non polar covalent
- two nuclei are equally attracted to the same pair of shared electrons
- exists between atoms with the same/similar electronegativity eg diatomic molecules
what is polar covalent
- two nuclei are unequally attracted to the same pair of shared electrons
- an atom with higher electronegativity has a greater attraction to the bonding electrons
- bonding electrons are pulled closer to the atom causing a permanent dipole
what happens if there is a large difference in electronegativity
then one atom loses its electron to the other
usually between metal and non metal elements
can a molecule have polar bonds and be non polar
yes
do polar or non polar molecules have permanent dipoles
polar molecules
is mp and bp higher in polar or non polar molecules and why
polar because they have increased intermolecular forces
example of non polar solvent
hexane
example of polar solvent
water
explain like dissolves like
polar substances are soluble in polar solvents and non polar substances are soluble in non polar solvents
what are the 3 van der waals forces in order of strength
ldfs, permanent dipole, hydrogen bonding
explain ldfs
electrons are constantly moving, can lead to uneven electron distribution at times which creates a temp dipole which induces another temp dipole in another atom
creates weak electrostatic force of attraction between the atoms
what elements does ldfs occur
all
which molecules will have a permanent dipole
polar molecules
what is hydrogen bonding
a type of permanent dipole force that occurs between hydrogen and NOF
how does ice melt
stable hydrogen bonds break and reform
melting point of ionic compounds
high
melting points of covalent networks
high
are ionic compounds solid at room temp
yes
are covalent networks solid at room temp
yes
what structure and bonding do all gasses and liquids
covalent molecular
what type of bonding had conduction as a solid
metallic
what kind of bonding has conduction as a liquid
metallic and ionic
what kind of bonding has conduction as solutions
ionic
