Chemical bonding CAQ

🥼 Chemical bonding Created Tags Explaining stability of different arrangements of same molecules by applying principles of VSEPR theory Tips For molecules with 5 electron regions, lone pair of electrons preferentially occupy the equatorial position as it is 90degrees to 2 other electron regions in axial position If lone pair is in axial position, it is 90 degree to 3 other electron regions and hence repulsion is not minimised The closer the electron regions are, the smaller bond angle, the more repulsion is experienced June 4 , 2025 7 2 4 PM Chemic al bonding 1

How the intermolecular forces arises Instantaneous dipole-induced dipole Id-id arises due to random movement of electrons giving rise to uneven distribution of electron cloud of a molecule, creating a instantaneous dipole which induces a similar dipole moment on adjacent molecules Hydrogen bonding hydrogen bonding which arises due to attraction between the lone pair electron of a highly electronegative element O atom in methanol) and a highly electron deficient H atom bonded directly to highly electronegative element O Permanent dipole-dipole Pd-pd arises due to overall net dipole moment electronegativity differences between 2 atoms creates a dipole moment for bond And these Dipoles not cancelled out completely partial positive charge atom on a molecule would have pd-pd interaction with partial negative charge atom on another molecule Explanation for AlCl3 having a higher boiling/melting point than SiCl4 (not in syllabus) Tips If Questions show a molecule with a larger MR having a lower bp/mp, itʼs usually because the other molecule exists as a dimer and hence end up Chemic al bonding 2

having a larger mr and stronger id-id Comparing bp/mp Explanation Ionic compounds Have giant ionic lattice structures held by strong ionic bonds between cations and anions Compare lattice energy, |L.E.| ∝ |q−q |/|r+r| by quoting the sizes of ions found in data booklet and charge . Hence one of the ionic compound has a smaller interionic distance and higher product of charges, More exothermic lattice energy, More energy required to break stronger ionic bonds, higher mp/bp Halogens/ halogen halides Has Id-id attraction between molecules. Down the group, increasing electron cloud size due to increasing mr and hence greater amount of energy to overcome stronger Id-id as dipoles are more easily induced and hence increasing bp and mp HF as the highest boiling point as more energy required to overcome the stronger hydrogen binding between HF Molecules than the id-Id Ionic compound vs simple covalent compound Ionic compound has a giant ionic lattice structure with strong ionic bond between oppositely charged ions while simple covalent compound has a simple molecular structure with weak imf of attractions such as Id-id between Chemic al bonding 3

Explanation molecules More energy to overcome stronger ionic bonds Polar vs polar molecule Both have a simple molecular structure consisting