Question

When $LiN{O_3}$ is heated, it gives oxide, $L{i_2}O$ whereas other alkali metal nitrates decompose to give corresponding:
A.Nitrite
B.Peroxide
C.Both nitrite and oxide
D.None of these

Answer 1

Alkali metals have high thermal and electrical conductivity. Each alkali metal atom has a single electron in its outermost shell. The group 1 elements are called alkali metals.

Complete step by step answer:
Now, due to the small size of lithium, it is very polarizing and favors the formation of $Li{O_2}$ .
The equation is as shown:
$4Li{O_3} \to 2L{i_2}O + 4N{O_2} + {O_2}$
While,
Other alkali metals nitrates decompose to give corresponding nitrite.
$NaN{O_3} \to NaN{O_2} + \dfrac{1}{2}{O_2}$
Therefore, nitrates tend to decompose on heating to give the metal oxide, brown fumes of nitrogen dioxide and oxygen.

Hence, option A is correct.

Addition information:
Having the largest radius and volume, alkali elements have the lowest density. So, they are very soft and can be cut with a knife. Lithium, Sodium and potassium are lighter than water and potassium has the lowest density among them. Moreover, with increasing atomic size, the valence electron gets shielded by the inner electrons and becomes easily removable with less energy requirement. Hence, the ionization energy decreases with increase in atomic number.

Note:
All the group 1 elements (alkali metals) are very reactive. They must be stored under oil to keep air and water away from them. They are solids at room temperature (except hydrogen) but have fairly low melting points.