This question concern the chemistry of the element Li, Na, K, Rb and Cs. In a and b case you should name the substance represented by letters. a) 'A' is the least dense of metals.
b) When metal 'B' is dropped on to water it melts into a small ball and moves rapidly around the surface. A gas, 'C', is given of and this burn with a lilac flame. A solution of 'D' is formed.
c) Write an equation for the reaction of 'B' with water.
d) What would you expect to see if solution 'D' was tested with universal indicator paper.
e) Explain why 'B' melt in to a small ball when it is dropped on to water.
f) 'E' burns in air with a yellow flame to form compound 'F'. write a word equation and balanced symbol equation for the reaction that occurs?

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.