Constructing Born-Haber Cycles A?Born-Haber cycle?is a specific application of?Hess's Law?for ionic compounds and enables us to calculate lattice enthalpy, which cannot be found by experiment The b...
Key Enthalpy Terms Ionisation energy The?ionisation?energy?(ΔHIE?) is the standard enthalpy change that occurs on the removal of 1 mole of electrons from 1 mole of gaseous atoms or positively charg...
Hybrid Orbitals Hybridisation The ground state of the electrons in a carbon atom is 1s22s22p2 This can be represented using a spin diagram as shown: Orbital spin diagram for carbon in the ground st...
Ozone Revisited We have seen previously that ozone is a molecule with two resonance structures leading to a resonance hybrid The two Lewis resonance structures for ozone The central oxygen atom has...
Delocalisation & Resonance The delocalisation of electrons can explain the structures of some species that don’t seem to fit with a Lewis structure Delocalised electrons are electrons in a mole...
Formal Charge A limitation of the model of covalent bonding is that when drawing Lewis structures for molecules, it is sometimes possible to come up with more than one structure while still obeying...
Further VSEPR Theory Revisiting Valence Shell Electron Pair Repulsion Theory (VSEPR) When an atom forms a covalent bond with another atom, the electrons in the different bonds and the non-bonding e...
Octet Rule Exceptions Incomplete octets We have seen previously that for elements below atomic number 20 the?octet rule?states that the atoms try to achieve 8 electrons in their valence shells, so ...
Sigma Bonds Bond overlap in covalent bonds A single?covalent?bond?is formed when two nonmetals combine Each atom that combines has an?atomic?orbital?containing a single unpaired electron When a cov...
