Chemical Bonding and Molecular Structure

  $F-Be-F$   $\mu =0$ $$

BF3 $\mu =0$

H2O $\mu \ne 0$ $$

NH3 $\mu \ne 0$ $$

CCl4 $\mu =0$ $$

HCl $\mu \ne 0$ $$

$\underset{\left(acid\right)}{H_{2}S}+\underset{Base}{H_{2}O}?H_3{O}^{+}+H{S}^{-}$

$\underset{\left(acid\right)}{H_{2}O}+\underset{\left(Base\right)}{N{H}_3}?N{H}_{4}OH$

With H₂S water acts like base and with NH₃ it acts like acid.

  $\underset{\left(acid\right)}{H_{2}S}+\underset{Base}{H_{2}O}?H_3{O}^{+}+H{S}^{-}$

$\underset{\left(acid\right)}{H_{2}O}+\underset{\left(Base\right)}{N{H}_3}?N{H}_{4}OH$

With H₂S water acts like base and with NH₃ it acts like acid.

The central atom of nitrogen has 5 valence electrons as per the electronic configuraion. During the formation of ${\mathrm{N}\mathrm{H}}_3$ , 3 valence electrons forms three sigma bonds with hydrogen and one lone electron pair is left.

• The steric number  of the ammonia molecule: SN=3 bonds +1 lone pair $=4$ total electron domains.
• As per the steric number, there is ${\mathrm{s}\mathrm{p}}^3$ hybridisation in ammonia.
• The lone pair causes repulsion, which leads to a trigonal pyramidal geometry with bond angles of ${107}^{?}$ .

The stability of the bond depends on various bond parameters including the bond length and bond energy. In general the shorter the bond, the lesser the bond energy will be, this leads to the stable molecule.

Since the bond order and energy of hydrogen molecule is lesser than the oxygen molecule, it is be more stable.

Kindly consider the following figure

  $\mathrm{}{\mathrm{C}\mathrm{N}}^{-}\Rightarrow 14$ electrons, so $\mathrm{B}.\mathrm{O}=3$ and diamagnetic.

You can check the below given table for the comarative differences between valence bond theory and molecular orbital theory.

The NO (Nitric Oxide) has 11 valence electrons while the NO? (Nitrosonium ion) has 10 valence electrons due to removal of one antibonding electron. Due to this, the bond order of NO increases from? 2.5 to 3 in the NO? (Nitrosonium ion). 

As per the NCERT, since the bond order of NO? (3) is higher than that of NO (2.5), the bond in Nitrosonium ion is stronger bond and the stronger the bond, the shorter bond length.

Hence bond length in NO? is shorter the NO.