Chemical Bonding and Molecular Structure

Molecule

Group of atoms existing together as a single species and having characteristic properties.

Chemical Bond

The attractive force which holds various constituents in a molecule together

Octet Rule

Atoms of different elements combine with each other in order to complete their octet.

Valency

The number of electrons shared, lost or donated by an atom while combining with another atom to reach stable noble gas configuration.

Ionic bond

Electrostatic force of attraction which holds two oppositely charged ions formed by the complete transfer of electrons from the electronegative atom to the electropositive atom.

Electrovalency

The number of atoms donated or accepted by an atom

Why are ionic bonds non-directional?

Ionic force extends throughout space and is equally strong in all directions.

Lattice Energy

Energy released when one mole of solids electrovalent compound is formed from its required number of corresponding ions in the gaseous state.

Greater the lattice enthalpy, greater the

stability of ionic compounds

Lattice enthalpy if calculated using

Born Haber Cycle

Covalent Bond

Bond formed by the mutual sharing of electrons b/w 2 atoms

Covalency

The number of electron pairs shared b/w two atoms

Bond length

The equilibrium distance b/w the centers of nuclei of two bonded atoms in a molecule.

Bond angle

The angle b/w the lines representing the orbitals containing the bonding electrons

Bond angle determines the ______ of the molecule

shape

Bond order

Number of bonds present b/w two atoms

Bond energy

the energy required to break 1 mole of bond b/w two atoms in their gaseous state so as to separate them into their gasses.

Resonance

The phenomenon of existence of several structures of same compound due to the delocalization of electrons.

Resonance hybrid

A compound, molecule or ion exhibiting resonance and represented in the written form as the average of two or more structural formulae separated each from the next by a double headed arrow.

Polar covalent bond

Covalent bond formed b/w two dissimilar atoms.

Non-polar covalent bond

Covalent bond formed b/w two similar atoms.

Dipole moment

The product of net positive or negative charge and the distance b/w the two charged ends.

Sigma bond

Covalent bond formed when two half-filled atomic orbitals overlap end to end along their axis.

Pi bond

Covalent bond formed when two half-filled atomic orbitals overlap sideways

Hybridisation

Mixing of atomic orbitals of the same atom having comparable energies to form an equal number of hybrid orbitals having same shape and energy.