Question

Both lithium and magnesium display several similar properties due to the diagonal relationship however, the one which is incorrect is:
A. Both form soluble bicarbonates
B. Both form nitrides
C. Nitrates of both \[{\rm{Li}}\] and \[{\rm{Mg}}\] yield \[{\rm{N}}{{\rm{O}}_{\rm{2}}}\] and \[{{\rm{O}}_{\rm{2}}}\] on heating
D. Both form basic carbonates

Answer 1

Hint: As per arrangement of elements in our modern periodic table, the first element of one group has similar properties as the second element of the next group has, this diagonal relationship can help us in deducing various similarities between these two diagonal elements.

Complete answer:
Here, we have lithium and magnesium. As per our modern periodic table, lithium belongs to group I and magnesium belongs to group II. Both of them are positioned diagonal to each other and are known to have a diagonal relationship. We can list out some similarities between the two as follows:
1. In their respective groups, we can see that both these elements are harder and lighter as compared to the other elements in their group.
2. Both these elements form nitrides upon reacting with nitrogen that have formula as ${\rm{L}}{{\rm{i}}_{\rm{3}}}{\rm{N}}$ and ${\rm{M}}{{\rm{g}}_{\rm{3}}}{{\rm{N}}_2}$.
3. The bicarbonates formed by these two elements are not solid but soluble though.
4. The reaction for thermal decomposition of lithium nitrate can be shown by the following chemical equation:
${\rm{4LiN}}{{\rm{O}}_{\rm{3}}} \to {\rm{2L}}{{\rm{i}}_{\rm{2}}}{\rm{O}} + {\rm{4N}}{{\rm{O}}_{\rm{2}}} + {{\rm{O}}_{\rm{2}}}$
Similarly, the reaction for thermal decomposition of magnesium nitrate can be shown by the following chemical equation:
${\rm{2Mg}}{\left( {{\rm{N}}{{\rm{O}}_{\rm{3}}}} \right)_2} \to {\rm{2MgO}} + {\rm{4N}}{{\rm{O}}_{\rm{2}}} + {{\rm{O}}_{\rm{2}}}$
So, we can say nitrates of both these elements give nitrogen dioxide and oxygen upon heating.
However, all the properties are not similar such as the nature of the carbonates formed by lithium and magnesium. We also know magnesium carbonate as Magnesite and it occurs in hydrated form. We can use it as an antacid because it is basic in nature. On the other hand, lithium carbonate is not basic in nature.

Hence, the correct option is D.

Note:
We can easily decompose the carbonates of lithium as well as magnesium by heating them to give respective oxide and carbon dioxide.