Which of the following can be used to extinguish a fire caused by sodium,potassium,and lithium?

Which of the following metals is found in the green colouring pigment chlorophyll of plants?

The solution of sodium metal in liquid ammonia is strongly reducing due to the presence of which of the following in the solution?

Thermal decomposition of lithium nitrate gives:

What is the correct order of increasing basic strength for $MgO, SrO, K_2O$,and $NiO$?

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