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

Match column $-I$ with column $-II$ :

Column $-I$	Column $-II$
$(a)$ Borax	$(p)$ $NaCl$
$(b)$ Carnallite	$(q)$ $KCl$
$(c)$ Rock salt	$(r)$ $KCl.MgCl_2.6H_2O$
$(d)$ Silvine	$(s)$ $Na_2B_4O_7.10H_2O$

With the increase in atomic weights,the melting points of the alkali metals:

Which of the following releases brown gas on heating?

$Al$ vessels should not be cleaned with materials containing washing soda because .............

Give the general electronic configuration of alkali metals and provide the electronic configuration for each element of the alkali metal group.