Question

Ions of an element of group 1 participate in the transmission of nerve signals and the transport of sugars and amino acids into cells. This element imparts a yellow colour to the flame in the flame test and forms an oxide and a peroxide with oxygen. Identify the element and write a chemical reaction to show the formation of its peroxide. Why does the element impart colour to the flame?

Answer 1

The yellow colour flame in the flame test indicates that the alkali metal must be sodium. $N{a}^{+}$ ions participate in the transmission of nerve signals. Sodium reacts with $O_2$ to form a mixture of sodium peroxide $\left(N{a}_2{O}_2\right)$ and sodium oxide $\left(N{a}_{2}O\right)$.

$4Na+O_2\to 2N{a}_{2}O$ (Minor)

$2N{a}_{2}O+O_2\to 2N{a}_2{O}_2$ (Major)

$2Na+O_2\to N{a}_2{O}_2$

When sodium metal or its salt is heated in Bunsen flame, the flame energy causes an excitation of the outermost electron which on reverting back to its initial energy level, gives out the absorbed energy as visible light and complementary colour of absorbed colour becomes visible in the flame.
That's why sodium imparts a yellow colour to the flame.