Which of the following salts form hydrates? $CaCl_2$ $(I)$,$NaCl$ $(II)$,$LiCl$ $(III)$,$BaCl_2$ $(IV)$,$KCl$ $(V)$

What are the common physical and chemical features of alkali metals?

Fill in the blanks:
$(1)$ $Li-Mg$ alloy is used to prepare ......
$(2)$ Colors of superoxides of alkali metals are ...... or ......
$(3)$ On combustion of lithium in the presence of air,it produces ...... and ......
$(4)$ On heating,lithium nitrate converts into ......

Alkali metals are powerful reducing agents because

The alkali metals which form normal oxide,peroxide,as well as superoxides are:

Which among the following elements has only one electron in the valence shell?