Chemical Bonding A Levels

ionic bonding

The electrostatic attraction between oppositely charged ions

lattic energy

the energy released when one mole of an ionic crystalline compound is formed from gaseous ions

Physical Properties of Ions + Why

High melting point, high boiling point, electrical conductor, soluble in polar solvents, hard and rigid, brittle —> due to strong electrostatic forces of attraction, mobile ions, charged parts of solvent attracted to opp. charged ions, -, repulsion between similarly charged ions

Fajan's Rule

The more polarised the anion, the higher the degree of covalent character

Polaris ability

distortion of electron cloud in anion

hybridazation

a process in which several atomic orbitals mix to form the same number of equivalent hybrid orbitals

covalent bonding

a bond formed when atoms share one or more pairs of electrons

Dative bond

A bond in which both electrons come from one of the atoms. Also known as coordinate bond.A

Atomic orbitals

the regions around the nucleus within which the electrons have the highest probability of being found

sp3 hybridization

A type of hybridization that results from the combination of the s orbital and all three p orbitals in the second energy level of carbon, resulting in four hybrid orbitals and occurs when a carbon atom is bonded to four other atoms. The geometric arrangement of those four hybrid orbitals is called tetrahedral.

sp2 hybridization

Combination of one s orbital and 2 p orbitals to form 3 equivalent sp2 hybrid orbitals. Trigonal Planar Arrangement

sp hybridization

a type of bonding where the 2s orbital mixes with only one of the three p-orbitals resulting in two sp orbitals and two remaining unchanged p orbitals and they are in linear arrangement

sigma bond

formed when two atomic orbitals overlap in a head-on manner [only 1 between 2 atoms]

pi bond

formed when two orbitals overlap in side on manner

Why does sp3 - spe3 have greatest bond length?

Greater the % of p character, the more diffused the hybrid orbital so the extent of sp3-sp3 overlap is the smallest

bond energy

the energy required to break 1 mol of a covalent bond between 2 atoms in gaseous state

Bond length

the distance between the nuclei of two bonded atoms

Effectiveness of orbital overlap

Smaller atoms can approach each other more closely —> more effective so stronger bond strength

bond order

the number of shared electron pairs between two atoms

bond polarity

a measure of the degree to which the electrons are shared unequally between two atoms in a chemical bond [more electronegative atom pulls the bonding electron towards itself resulting in charge separation]

instantaneous dipole-induced dipole

instantaneous dipole in one particle induces a dipole in another, resulting in an attraction between them

Permanent dipole-dipole interactions

An attractive force between permanent dipoles in neighbouring polar molecules due to non symmetrical distribution of electrons

hydrogen bonding

the intermolecular force in which a hydrogen atom that is bonded to a highly electronegative atom [N, O or F] is attracted to an unshared pair of electrons of an electronegative atom in a nearby molecule [N, O or F]

Valence Shell Electron Pair Repulsion Principles

Electrons pairs around central atoms are arranged as far apart as possible to minimise electrostatic repulsion
Lone pair - lone pair > lone pair - bond pair > bond pair - bond pair

metallic bonding

the chemical bonding that results from the attraction between metal atoms and the surrounding sea of electrons