chemistry

Question 1

define molecular orbital theory

Answer 1

proposed by hund and mullikan .
acd to this theory, hund and mullikan proposed the concept of energy and symmetry where they explain every possible combination of molecules and formation of molecular orbital.

Question 2

diff. bonding and anti-bonding

Answer 2

b.o is formed by additive overlap of atomic orbital.
formation takes place when two lobes of atomic orbital have same sign.
bo contributes towards stability of atom.

a.o it is formed by substractive overlap.
formation takes place when two lobes of ao have different or opposite sign.
every electron contributes towards unstability of molecule.

Question 3

description of linear combination of atomic orbital.

Answer 3

1. the atoms which are going to be combined must have same energy and same symmetry.
2. after combination of atom molecules are formed.
3. electrons are present in molecular orbital with a pair of two, they entered in molecular orbital singly before they pair.
4. electrons are filled in molecular orbital as per the increasing order of energy.

Question 4

write the bond order formula.

Answer 4

bond order=(Nb- Na)/2

Question 5

why H2 cannot exist?

Answer 5

as H2 molecule is a hypothetical gas which does not exist in open environment.
H2 is considered as a inert gas. the presence of H2 is not seen openly in the nature, since it is having B.O=0, due to which the molecule dosen’t exist in nature.