Energy level diagram for Molecular orbitals

Energy level diagram for Molecular orbitals The first ten molecular orbitals may be arranged in order of energy as follow: σ(1s) <σ∗(1s) < σ(2s) <σ∗(2s) < π(2px) = π(2py) < σ(2pz) < π∗(2px) =π∗(2py) <π∗( 2pz) Relationship between electronic configuration and Molecular behaviour 1)Stability of molecules in terms of bonding and antibonding electrons Number of…

Types Of Molecular Orbital Formed

Types of molecular orbitals formed 1)If two atomic orbitals overlap along the internuclear axis ,the molecular orbital formed is called σ molecular orbital. 2)If two atomic orbitals overlap sideways, the molecular orbital formed is called π molecular orbital. 3)s orbitals are spherically symmetrical ,their wave function has the same size in all the directions. 4)In p-…

Shapes Of Molecules

Shape of beryllium fluoride( BeF2) molecule Atomic number of Be= 4 Electronic configuration in ground state is 1s2 2s2 Electronic configuration in excited state is 1s2 2s1 2px1 one 2s orbital and one 2p orbital undergo sp hybridisation to form two half filled sp hybrid orbitals which are oriented at an angle of 180°. They…

Hydrogen Bonding

Whenever a molecule contains a hydrogen atom linked to a highly electronegative atom, this atom attracts the shared pair of electrons more and so this end of the molecules becomes slightly negative while the other end become slightly positive. The negative end of one molecule attracts the positive end of the other and as a…

Molecular Orbital Theory

Molecular orbital theory Features of Molecular orbital theory 1)The atomic orbitals overlap to form new orbitals called molecular orbitals. When two atomic orbitals overlap or combine ,they lose their identity and form new orbitals. The new orbitals thus formed are called molecular orbitals. 2)Molecular orbitals are the energy states of a molecule in which the…

Resonance

In case of certain molecules, a single Lewis structure cannot explain all the properties of the molecule. The molecule is then supposed to have many structures ,each of which can explain most of the properties of the molecules but none can explain all the properties of the molecule. The actual structure is in between of…

Coordinate Bond

Certain atoms which have complete octets can donate their valence electrons which are not involved in bond formation ,to other atoms, which are short of electron. These donated electrons are, therefore, lone pair of electrons and are shared by both the atoms. When in the formation of a bond, the electron pair is donated by…

Hybridisation

Hybridisation is defined as the mixing of the atomic orbitals belonging to the same atom but having slightly different energies so that a redistribution of energy takes place between them resulting in the formation of new orbitals of equal energies and identical shape. The new orbitals thus formed are known as hybrid orbitals. Important points…

Fajan’s Rules

When a cation approaches an anion, the electron cloud of the anion is attracted towards a cation and hence gets distorted. The effect is called polarisation of the anion. The power of cation to polarise anion is called its polarising power and tendency of the anion to get polarised is called polarisability. The greater is the polarisation…

Dipole Moments

In a polar molecule, there are two poles present in the molecule.Hence, the molecule is said to possess an electric dipole.Since the molecule as a whole is electrically neutral ,the negative charges is always equal in magnitude to the positive charge. The product of magnitude of negative or positive charge(q) and the distance between the…

Polar and Non-Polar Covalent Bond

Non-polar covalent bonds If two similar atoms come close to each other and form a bond by sharing their electrons, the shared electrons are equally attracted by the two atoms as the electronegativity of the atoms is same. Hence no poles are developed. This leads to the formation of completely non-polar bonds. If two hydrogen…

Bond Characteristics

Bond Length When atoms come closer to each other, attraction takes place between them and ,therefore, the potential energy of the system keeps on decreasing till at a particular distance, the potential energy is minimum. If the atoms are further brought closer ,the repulsion start and therefore, the potential energy of the system begins to…

Types Of Covalent Bond

Depending upon the type of overlapping, the covalent bonds are mainly of two types: Sigma bond (σ)  When a bond is formed between two atoms by the overlap of their atomic orbitals along the internuclear axis, the bond formed is called sigma bond The overlapping along the internuclear axis can take place in any one…

Valence Bond Theory

This theory was put forward by Heitler and London in 1927 and was further developed by Pauling and others. In terms of energy When the two atoms are far apart from each other there is no interaction between them. When they come closer to each other ,the new forces come into operation. These forces are…

Valence Shell Electron Pair Repulsion Theory

The first simple theory that was put forward to explain the shape of the molecule is known as Valence Shell Electron Pair Repulsion Theory. This theory was given by Sidgwick and Powell in 1940. 1)The central atom is linked to other atoms by covalent bonds which are formed by sharing of electrons. 2)The central atom…

Covalent Bond

The bond formed between the two atoms by mutual sharing of electrons between them so as to complete their octets or duplets in case of elements having only one shell is called covalent bond and the number of electrons contributed by each atom is known as covalency. Examples Two chlorine atoms combine to produce chlorine…

Ionic Bond

When a bond is formed by complete transference of electrons from one atom to another so as to complete their outermost orbit by acquiring 8 electrons or 2 electrons in case of hydrogen, lithium etc and hence acquire the stable nearest noble gas configuration, the bond form is called ionic bond or electrovalent bond. On…

Lewis Symbols

A group of atoms existing together as one species and having characteristic properties is called a molecule. This force which holds the atoms together within a molecule is called a covalent bond. Noble gases neither combine chemically with any other element nor among themselves i.e.they are chemically inert. Noble gases are inactive or stable because…