Molecular Orbital Theory (QUIZ-1) 1 / 15 On the basis of molecular orbital theory, select the most appropriate option. The bond order of O2 is 2.5 and it is paramagnetic The bond order of O2 is 1.5 and it is paramagnetic The bond order of O2 is 2 and it is diamagnetic The bond order of O2 is 2 and it is paramagnetic Oxygen is paramagnetic in nature and its bond order is 2. It is an exceptional case. 2 / 15 Arrange the following molecules in decreasing bond length. 1 2 3 4 The bond length is inversely proportional to the bond order. Therefore, the correct is:O22- > O2– > O2 > O2+. 3 / 15 Bond Order of O2, F2, N2 respectively are __________ +1, +2, +3 +2, +3, +1 +2, +1, +3 +3, +2, +1 Bond Order=[[Number of electrons in bonding molecular orbital]-[Number of electrons in antibonding molecular orbital]]/2. 4 / 15 The filling of molecular orbital takes place according to __________ The Aufbau Principle Pauli Exclusion Principle Hund’s rule of maximum multiplicity All of the mentioned According to these principles, molecular orbitals are filled in order of increasing energy. Two electrons in the same orbital cannot have the same set of all four quantum numbers identical. 5 / 15 If the sign of the wave function is unchanged when the orbital is reflected about its centre, the orbital is ______________ Gerade Ungerade Gerade as well as Ungerade None of the mentioned If the sign of the wave function is unchanged when the orbital is reflected about its center (i.e., x, y and z are replaced by –x, -y and –z), the orbital is gerade. 6 / 15 Which of the following molecule is not true about paramagnetic molecules? Attracted by the magnetic field A molecular orbital is singly occupied An example is oxygen molecule Repelled by the magnetic field Paramagnetic molecules are attracted by the magnetic field and orbitals are singly occupied. O2 is an example. Whereas diamagnetic molecules are repelled by the magnetic field, so the option is wrong. 7 / 15 What do you think is the relationship between bond order and bond length? Directly proportional Indirectly proportional No relation Cannot predict The bond length has defined the distance between two atoms in a molecule. The bond order depends on the bond length between two atoms in a molecule. As the bond length increases the bond decreases and vice-versa. 8 / 15 What’s the bond order of Oxygen? 3 2 1 0 The formula of bond order is given by 1⁄2(NB – NA) When NB is bonding orbitals and NA is the number of anti-bonding orbitals. In Oxygen, bond order = 1/2(10-6) = 2. When it’s zero the molecule cannot be formed. 9 / 15 Take NA as the number of Anti-bonding molecular orbitals and NB as the number of Bonding molecular orbitals. The molecule is stable when NA ____________ NB. is greater than is equal to is less than is greater than or equal to When a molecule consists both bonding molecular orbitals and anti-bonding molecular orbitals, the higher the number of bonding orbitals, the more the bonding influence and the more stable the molecule will be and vice-versa. 10 / 15 Which of the bonding orbital has greater energy comparatively? Both Bonding molecular orbital and Anti-bonding molecular orbital have the same energy The energy of Bonding molecular orbital and Anti-bonding molecular orbital depends on the situation Bonding molecular orbital Anti-bonding molecular orbital An electron that enters bonding orbitals stabilizes the molecule as it’ in between two nuclei. Whereas when an electron is entered into the anti-bonding orbital, it needs to pull an electron away from the nucleus. 11 / 15 Which of the following is a condition for the combination of atomic orbitals? Combining atomic orbitals need not have equal energy Combining atomic orbitals must have symmetry as per molecular axis Combining atomic orbitals must overlap to a minimum extent For combining atomic orbitals, X-axis should be taken as a molecular axis Combining atomic orbitals must have symmetry as per molecular axis is true. The corrected statements are combining atomic orbitals must have equal energy, must overlap to the maximum extent and Z-axis should be taken as the molecular axis. 12 / 15 Stability increases, as the energy ___________ increases doesn’t change decreases increases and then decreases As the stability increases, the energy of that substance decreases. The higher the energy, the less stable the molecule. So stability is inversely proportional to the energy. This can be seen in any part of the universe. 13 / 15 Combination of two atomic orbitals results in the formation of two molecular orbitals namely _________ one bonding and one non-bonding orbital two bonding orbitals two non-bonding orbitals two bonding and non-bonding orbitals F. Hund and R.F. Mullikan proposed Molecular orbital theory in the year 1932. According to this theory, the combination of two atomic orbitals results in the formation of two molecular orbitals namely one bonding and one non-bonding orbital. 14 / 15 1 2 3 4 15 / 15 Among the following molecules/ions,which one is diamagnetic and has the shortest bond length? 1 2 3 4 5 Your score isThe average score is 73% 0% Restart quiz
