Chemistry MCQs for NEET — Practice Questions with Answers

The correct relation is: Bond order is directly proportional to bond energy and inversely proportional to bond length. This means higher bond order indicates greater bond energy and shorter bond length, contributing to the stability of the molecule. Therefore, the relation is $Bond order \alpha Bond energy \alpha {1 \over Bond length} \alpha stability$.

factual

Bond order $O_2^+ = 2.5 $ $ O_2 = 2 $ $ O_2^- = 1.5 $ $ O_2 ^ {-2} = 1 $

Electrovalent bond (ionic bond) formation involves transfer of electrons from one atom to another, typically between a metal and a nonmetal. In the given configurations, element Q ($1s^2, 2s^2, 2p^5$) is one electron short of a stable noble gas configuration (like element R with $1s^2, 2s^2, 2p^6$). Hence, Q has a strong tendency to gain an electron, making it highly electrovalent.

The stability of diatomic molecules can be compared using Molecular Orbital Theory. According to this theory, the bond order of $O_2$ is 2, which makes it more stable compared to $O_2^-$ (bond order 1.5), $Ne_2^+$ (bond order 0.5, unstable), and $F_2$ (bond order 1). Therefore, $O_2$ is the most stable species among the given options.

Metallic bonds are characterized by a 'sea of electrons' that are delocalized over a lattice of metal cations. The metallic bond is non-directional, meaning that the strength of the bond is the same in all directions, unlike covalent bonds which are directional. Therefore, the statement that 'Directional property is shown by metal' is incorrect.

Number of H - bond form by unpaired electrons of liquid NH3 , H2O and HF respectively are  1, 2, 1