According to molecular orbital theory, the correct order of energy for \(\sigma_{2p}\) orbital is :
\(\mathrm{C_{2} \lt N_{2} \gt O_{2}}\)
In second-period homonuclear diatomics the \(\sigma_{2s}\) and \(\sigma_{2p}\) orbitals have the same symmetry and interact (s–p mixing). The mixing pushes \(\sigma_{2p}\) upward, so its position is judged against the \(\pi_{2p}\) level of the same molecule.
O2: the 2s–2p gap of oxygen is large, s–p mixing is weak, and \(\sigma_{2p}\) lies below \(\pi_{2p}\) (configuration … \(\sigma_{2p}^{2}\pi_{2p}^{4}\pi_{2p}^{*2}\)).
N2: \(\sigma_{2p}\) is pushed clearly above \(\pi_{2p}\) and is the HOMO; photoelectron spectra show its ionisation energy (15.6 eV) is about 1.1 eV lower than that of the \(\pi_{2p}\) level (16.7 eV).
C2: the ground configuration is … \(\pi_{2p}^{4}\) with \(\sigma_{2p}\) empty, and the state with an electron promoted into \(\sigma_{2p}\) lies very close in energy, so in C2 the \(\sigma_{2p}\) level is only marginally above \(\pi_{2p}\).
So the relative raising of \(\sigma_{2p}\) is greatest in N2, smaller in C2, and in O2 the level drops below \(\pi_{2p}\): C2 < N2 and N2 > O2.
Therefore the order is C2 < N2 > O2.
Hence, \(\mathrm{C_{2} \lt N_{2} \gt O_{2}}\).
Important Questions from Mixed Topic (MH-SET)
.................... is a client server application that identifies each host on the internet with a unique user-friendly name.
Every OS has a ................ or .......... which primarily resides in the main memory of the computer to perform some of the basic functions of the OS.
(i) Kernel
(ii) Interface
(iii) Nucleus
(iv) Compiler
Codes:
Which of the following are referred to as low level language?
(i) Machine language
(ii) Assembly language
(iii) High level language
(iv) Natural language
Codes:
Match the following:
List I List II (a) New York Public Library (i) Shelv AR (b) Miami University Augmented Research Group (ii) Smart library (c) Oula University Library (iii) Wolf Walk (d) North Carolina State University (iv) Find the future Codes:
Which part of the QR code represents the encoded data?
