Explain the meanings of malleable and ductile.

$(i)$ Write the electron-dot structures for sodium,oxygen,and magnesium.
$(ii)$ Show the formation of $Na_{2}O$ and $MgO$ by the transfer of electrons.
$(iii)$ What are the ions present in these compounds?

Samples of four metals $A$,$B$,$C$ and $D$ were taken and added to the following solutions one by one. The results obtained have been tabulated as follows.

Metal	Iron $(II)$ sulphate	Copper $(II)$ sulphate	Zinc sulphate	Silver nitrate
$A$	No reaction	Displacement	No reaction	Displacement
$B$	Displacement	Displacement	No reaction	Displacement
$C$	No reaction	No reaction	No reaction	Displacement
$D$	No reaction	No reaction	No reaction	No reaction

Use the table above to answer the following questions about metals $A$,$B$,$C$ and $D$:
$(i)$ Which is the most reactive metal?
$(ii)$ What would you observe if $B$ is added to a solution of Copper $(II)$ sulphate?
$(iii)$ Arrange the metals $A$,$B$,$C$ and $D$ in the order of decreasing reactivity.

Give reasons: Aluminium is a highly reactive metal,yet it is used to make utensils for cooking.

Name two metals which will displace hydrogen from dilute acids,and two metals which will not.

Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).