Explain why $\mathrm{CO}_3^{2-}$ ion cannot be represented by a single Lewis structure. How can it be best represented?
A single Lewis structure of $\mathrm{CO}_3^{2-}$ ion cannot explain all the properties of this ion. It can be represented as a resonance hybrid of the following structures
If, it were represented only by one structure, there should be two types of bonds, i.e., $\mathrm{C}=\mathrm{O}$ double bond and C — O single bonds but actually all bonds are found to be identical with same bond length and same bond strength.
Predict the hybridisation of each carbon in the molecule of organic compound given below. Also indicate the total number of sigma and pi-bonds in this molecule.
The hybridisation and type of bonds of each carbon in the molecule given below
Group the following as linear and non-linear molecules.
$$\mathrm{H}_2 \mathrm{O}, \mathrm{HOCl}, \mathrm{BeCl}_2, \mathrm{Cl}_2 \mathrm{O}$$
The structure of the given molecules are
Therefore, only BeCl$$_2$$ is linear and rest of the molecules are non-linear.
Elements $X, Y$ and $Z$ have 4, 5 and 7 valence electrons respectively.
(a) Write the molecular formula of the compounds formed by these elements individually with hydrogen.
(b) Which of these compounds will have the highest dipole moment?
(a) 
(b) $Z$ has seven electrons in its valence shell. It is the most electronegative element. Therefore, HZ will have the highest dipole moment.
Draw the resonating structure of
(a) ozone molecule
(b) nitrate ion
(a) The resonating structure of ozone molecule may be written as
(b) The resonating structure of nitrate ion $\left(\mathrm{NO}_3^{-}\right)$ is
